(转载)Everynes NES Hardware Specifications
原文:
NES Specifications
| Everynes - Nocash NES Specs |
Everynes Hardware Specifications
Tech Data
Memory Maps
I/O Map
Picture Processing Unit (PPU)
Audio Processing Unit (APU)
Controllers
Cartridges and Mappers
Famicom Disk System (FDS)
Hardware Pin-Outs
CPU 65XX Microprocessor
About Everynes
| Tech Data |
Overall Specs
CPU 2A03 - customized 6502 CPU - audio - does not contain support for decimal
The NTSC NES runs at 1.7897725MHz, and 1.7734474MHz for PAL.
NMIs may be generated by PPU each VBlank.
IRQs may be generated by APU and by external hardware.
Internal Memory: 2K WRAM, 2K VRAM, 256 Bytes SPR-RAM, and Palette/Registers
The cartridge connector also passes audio in and out of the cartridge, to
allow for external sound chips to be mixed in with the Famicom audio.
Original Famicom (Family Computer) (1983) (Japan)
60-pin cartridge slot, with external sound-input, without lockout chip.
Two joypads directly attached to console, Joypad 1 with Start/Select buttons,
Joypad 2 with microphone, but without Start/Select. 15pin Expansion port for
further controllers. Video RF-Output only.
"During its first year, people found the Famicom to be unreliable, with
programming errors and freezing rampant. Yamauchi recalled all sold Famicom
systems, and put the Famicom out of production until the errors were fixed.
The Famicom was re-released with a new motherboard."
Original NES (Nintendo Entertainment System) (1985) (US, Europe, Australia)
Same as Famicom, but with slightly different pin-outs on cartridge slot, and
controllers/expansion ports: Front-loading 72-pin cartridge slot, without
external sound-input on cartridge slot, without microphone on joypads, with
lockout chip.
Newer Famicom, AV Famicom (1993-1995)
60-pin cartridge slot, with external sound-input, without lockout chip.
Includes NES-style joystick connectors, plus the original 15pin Famicom
Expansion port. Doesn't have microphone. Video AV-Output only.
Newer NES (1993-1995)
Top-loading 72-pin cartridge slot, without external sound-input, without
lockout chip. Poorer video signal than old NES. Video WHAT?-output only.
VS Unisystem
Arcade Machine. Coin-detect inputs, eight Dip-switches, different palette.
Play Choice 10
Arcade Machine with 10 cartridge slots. Uses Z80 as second CPU.
| Memory Maps |
Internal Memory: 2K WRAM, 2K VRAM, 256 Bytes SPR-RAM, and Palette/Registers
CPU Memory Map (16bit buswidth, 0-FFFFh)
0000h-07FFh Internal 2K Work RAM (mirrored to 800h-1FFFh) 2000h-2007h Internal PPU Registers (mirrored to 2008h-3FFFh) 4000h-4017h Internal APU Registers 4018h-5FFFh Cartridge Expansion Area almost 8K 6000h-7FFFh Cartridge SRAM Area 8K 8000h-FFFFh Cartridge PRG-ROM Area 32K |
CPU Reset vector located at [FFFC], even smaller carts must have memory at that location. Larger carts may use whatever external mappers to access more than the usual 32K.
PPU Memory Map (14bit buswidth, 0-3FFFh)
0000h-0FFFh Pattern Table 0 (4K) (256 Tiles) 1000h-1FFFh Pattern Table 1 (4K) (256 Tiles) 2000h-23FFh Name Table 0 and Attribute Table 0 (1K) (32x30 BG Map) 2400h-27FFh Name Table 1 and Attribute Table 1 (1K) (32x30 BG Map) 2800h-2BFFh Name Table 2 and Attribute Table 2 (1K) (32x30 BG Map) 2C00h-2FFFh Name Table 3 and Attribute Table 3 (1K) (32x30 BG Map) 3000h-3EFFh Mirror of 2000h-2EFFh 3F00h-3F1Fh Background and Sprite Palettes (25 entries used) 3F20h-3FFFh Mirrors of 3F00h-3F1Fh |
Note: The NES contains only 2K built-in VRAM, which can be used for whatever purpose (for example, as two Name Tables, or as one Name Table plus 64 Tiles). Palette Memory is built-in as well. Any additional VRAM (or, more regulary, VROM) is located in the cartridge, which may also contain mapping hardware to access more than 12K of video memory.
SPR-RAM Memory Map (8bit buswidth, 0-FFh)
00-FF Sprite Attributes (256 bytes, for 64 sprites / 4 bytes each) |
Sprite RAM is directly built-in in the PPU chip. SPR-RAM is not connected to CPU or PPU bus, and can be accessed via I/O Ports only.
| I/O Map |
I/O Map
2000h - PPU Control Register 1 (W) 2001h - PPU Control Register 2 (W) 2002h - PPU Status Register (R) 2003h - SPR-RAM Address Register (W) 2004h - SPR-RAM Data Register (RW) 2005h - PPU Background Scrolling Offset (W2) 2006h - VRAM Address Register (W2) 2007h - VRAM Read/Write Data Register (RW) 4000h - APU Channel 1 (Rectangle) Volume/Decay 4001h - APU Channel 1 (Rectangle) Sweep 4002h - APU Channel 1 (Rectangle) Frequency 4003h - APU Channel 1 (Rectangle) Length 4004h - APU Channel 2 (Rectangle) Volume/Decay 4005h - APU Channel 2 (Rectangle) Sweep 4006h - APU Channel 2 (Rectangle) Frequency 4007h - APU Channel 2 (Rectangle) Length 4008h - APU Channel 3 (Triangle) Linear Counter 4009h - APU Channel 3 (Triangle) N/A 400Ah - APU Channel 3 (Triangle) Frequency 400Bh - APU Channel 3 (Triangle) Length 400Ch - APU Channel 4 (Noise) Volume/Decay 400Dh - APU Channel 4 (Noise) N/A 400Eh - APU Channel 4 (Noise) Frequency 400Fh - APU Channel 4 (Noise) Length 4010h - APU Channel 5 (DMC) Play mode and DMA frequency 4011h - APU Channel 5 (DMC) Delta counter load register 4012h - APU Channel 5 (DMC) Address load register 4013h - APU Channel 5 (DMC) Length register 4014h - SPR-RAM DMA Register 4015h - DMC/IRQ/length counter status/channel enable register (RW) 4016h - Joypad #1 (RW) 4017h - Joypad #2/APU SOFTCLK (RW) |
Additionally, external hardware may contain further ports:
4020h - VS Unisystem Coin Acknowlege 4020h-40FFh - Famicom Disk System (FDS) 4100h-FFFFh - Various addresses used by various cartridge mappers |
| Picture Processing Unit (PPU) |
PPU Control and Status Registers
PPU SPR-RAM Access Registers
PPU VRAM Access Registers
PPU Scrolling
PPU Tile Memory
PPU Background
PPU Sprites
PPU Palettes
PPU Dimensions & Timings
Based on "Nintendo Entertainment System Documentation" Version 2.00 by Jeremy
Chadwick aka Y0SHi aka JDC. Which was itself based on "Nintendo Entertainment
System Architecture" by Marat Fayzullin.
| PPU Control and Status Registers |
2000h - PPU Control Register 1 (W)
Bit7 Execute NMI on VBlank (0=Disabled, 1=Enabled) Bit6 PPU Master/Slave Selection (0=Master, 1=Slave) (Not used in NES) Bit5 Sprite Size (0=8x8, 1=8x16) Bit4 Pattern Table Address Background (0=VRAM 0000h, 1=VRAM 1000h) Bit3 Pattern Table Address 8x8 Sprites (0=VRAM 0000h, 1=VRAM 1000h) Bit2 Port 2007h VRAM Address Increment (0=Increment by 1, 1=Increment by 32) Bit1-0 Name Table Scroll Address (0-3=VRAM 2000h,2400h,2800h,2C00h) (That is, Bit0=Horizontal Scroll by 256, Bit1=Vertical Scroll by 240) |
2001h - PPU Control Register 2 (W)
Bit7-5 Color Emphasis (0=Normal, 1-7=Emphasis) (see Palettes chapter) Bit4 Sprite Visibility (0=Not displayed, 1=Displayed) Bit3 Background Visibility (0=Not displayed, 1=Displayed) Bit2 Sprite Clipping (0=Hide in left 8-pixel column, 1=No clipping) Bit1 Background Clipping (0=Hide in left 8-pixel column, 1=No clipping) Bit0 Monochrome Mode (0=Color, 1=Monochrome) (see Palettes chapter) |
If both sprites and BG are disabled (Bit 3,4=0) then video output is disabled, and VRAM can be accessed at any time (instead of during VBlank only). However, SPR-RAM does no longer receive refresh cycles, and its content will gradually degrade when the display is disabled.
2002h - PPU Status Register (R)
Bit7 VBlank Flag (1=VBlank) Bit6 Sprite 0 Hit (1=Background-to-Sprite0 collision) Bit5 Lost Sprites (1=More than 8 sprites in 1 scanline) Bit4-0 Not used (Undefined garbage) |
Reading resets the 1st/2nd-write flipflop (used by Port 2005h and 2006h).
Reading resets Bit 7, can be used to acknowledge NMIs, Bit 7 is also
automatically reset at the end of VBlank, so manual acknowledge is normally
not required (unless one wants to free the NMI signal for external NMI
inputs).
Status Notes
VBlank flag is set in each frame, even if the display is fully disabled, and
even if NMIs are disabled. Hit flag may become set only if both BG and OBJ
are enabled. Lost Sprites flag may become set only if video is enabled (ie.
BG or OBJ must be on). For info about the "Not used" status bits, and some
other PPU bits see:
Unpredictable Things
| PPU SPR-RAM Access Registers |
2003h - SPR-RAM Address Register (W)
D7-D0: 8bit address in SPR-RAM (00h-FFh) |
Specifies the destination address in Sprite RAM for use with Port 2004h (Single byte write), and Port 4014h (256 bytes DMA transfer).
This register is internally used during rendering (and typically contains 00h
at the begin of the VBlank period).
2004h - SPR-RAM Data Register (Read/Write)
D7-D0: 8bit data written to SPR-RAM. |
Read/write data to/from selected address in Sprite RAM.
The Port 2003h address is auto-incremented by 1 after each <write> to 2004h.
The address is NOT auto-incremented after <reading> from 2004h.
4014h - Sprite DMA Register (W)
Transfers 256 bytes from CPU Memory area into SPR-RAM. The transfer takes 512
CPU clock cycles, two cycles per byte, the transfer starts about immediately
after writing to 4014h: The CPU either fetches the first byte of the next
instruction, and then begins DMA, or fetches and executes the next
instruction, and then begins DMA. The CPU is halted during transfer.
Bit7-0 Upper 8bit of source address (Source=N*100h) (Lower bits are zero) |
Data is written to Port 2004h. The destination address in SPR-RAM is thus [2003h], which should be normally initialized to zero - unless one wants to "rotate" the target area, which may be useful when implementing more than eight (flickering) sprites per scanline.
Notes
SPR-RAM should be accessed during VBlank only. SPR-RAM is dynamic memory,
refreshed during rendering, it does no longer receive refresh cycles (and
will lose its content) when the display is disabled (by clearing both Bit 3
and 4 in Port 2001h).
| PPU VRAM Access Registers |
Registers used to Read and Write VRAM data, and for Background Scrolling.
The CPU can Read/Write VRAM during VBlank only - because the PPU permanently
accesses VRAM during rendering (even in HBlank phases), and because the PPU
uses the VRAM Address register as scratch pointer. Respectively, the address
in Port 2006h is destroyed after rendering, and must be re-initialized before
using Port 2007h.
1st/2nd Write
Below Port 2005h and 2006h require two 8bit writes to receive a 16bit
parameter, the current state (1st or 2nd write) is memorized in a single
flipflop, which is shared for BOTH Port 2005h and 2006h. The flipflop is
reset when reading from PPU Status Register Port 2002h (the next write will
be then treated as 1st write) (and of course it is also reset after any 2nd
write).
2005h - PPU Background Scrolling Offset (W2)
Defines the coordinates of the upper-left background pixel, together with PPU
Control Register 1, Port 2000h, Bits 0-1).
Port 2005h-1st write: Horizontal Scroll Origin (X*1) (0-255) Port 2005h-2nd write: Vertical Scroll Origin (Y*1) (0-239) Port 2000h-Bit0: Horizontal Name Table Origin (X*256) Port 2000h-Bit1: Vertical Name Table Origin (Y*240) |
Caution: The above scroll reload settings are overwritten by writes to Port 2006h. See PPU Scrolling chapter for more info.
2006h - VRAM Address Register (W2)
Used to specify the 14bit VRAM Address for use with Port 2007h.
Port 2006h-1st write: VRAM Address Pointer MSB (6bit) Port 2006h-2nd write: VRAM Address Pointer LSB (8bit) |
Caution: Writes to Port 2006h are overwriting scroll reload bits (in Port 2005h and Bit0-1 of Port 2000h). And, the PPU uses the Port 2006h register internally during rendering, when the display is enabled one should thus reinitialize Port 2006h at begin of VBlank before accessing VRAM via Port 2007h.
2007h - VRAM Read/Write Data Register (RW)
The PPU will auto-increment the VRAM address (selected via Port 2006h) after
each read/write from/to Port 2007h by 1 or 32 (depending on Bit2 of $2000).
Bit7-0 8bit data read/written from/to VRAM |
Caution: Reading from VRAM 0000h-3EFFh loads the desired value into a latch, and returns the OLD content of the latch to the CPU. After changing the address one should thus always issue a dummy read to flush the old content. However, reading from Palette memory VRAM 3F00h-3FFFh, or writing to VRAM 0000-3FFFh does directly access the desired address.
| PPU Scrolling |
The PPU allows to scroll the background pixelwise horizontally and
vertically. The total scroll-able area is 512x480 pixels (though the full
size can be usedwith external memory only, see Name Tables chapter), of which
circa 256x240 pixels are displayed (see visible screen resolution).
Vertical offsets 240-255 (aka Tile Rows 30-31) will cause garbage Tile
numbers to be fetched from the Attribute Table (instead of from Name Table),
after line 255 it will wrap to line 0, but without producing a carry-out to
the Name Table Address.
Scroll Pointer and Reload Registers
Scrolling relies on a Pointer register (Port 2006h), and on a Reload register
(Port 2005h, and Bit0-1 of Port 2000h). The Pointer is automatically
incremented by the hardware during rendering, and points to the currently
drawn tile row, the same pointer register is also used by software to access
VRAM during VBlank or when the display is disabled. The Reload value defines
the horizontal and vertical origin of upper-left pixel, the reload value is
automatically loaded into the Pointer at the end of the vblank period
(vertical reload bits), and at the begin of each scanline (horizontal reload
bits). The relation between Pointer and Reload bits is:
VRAM-Pointer Scroll-Reload A8 2006h/1st-Bit0 <--> Y*64 2005h/2nd-Bit6 A9 2006h/1st-Bit1 <--> Y*128 2005h/2nd-Bit7 A10 2006h/1st-Bit2 <--> X*256 2000h-Bit0 A11 2006h/1st-Bit3 <--> Y*240 2000h-Bit1 A12 2006h/1st-Bit4 <--> Y*1 2005h/2nd-Bit0 A13 2006h/1st-Bit5 <--> Y*2 2005h/2nd-Bit1 - 2006h/1st-Bit6 <--> Y*4 2005h/2nd-Bit2 - 2006h/1st-Bit7 <--> - - A0 2006h/2nd-Bit0 <--> X*8 2005h/1st-Bit3 A1 2006h/2nd-Bit1 <--> X*16 2005h/1st-Bit4 A2 2006h/2nd-Bit2 <--> X*32 2005h/1st-Bit5 A3 2006h/2nd-Bit3 <--> X*64 2005h/1st-Bit6 A4 2006h/2nd-Bit4 <--> X*128 2005h/1st-Bit7 A5 2006h/2nd-Bit5 <--> Y*8 2005h/2nd-Bit3 A6 2006h/2nd-Bit6 <--> Y*16 2005h/2nd-Bit4 A7 2006h/2nd-Bit7 <--> Y*32 2005h/2nd-Bit5 - - <--> X*1 2005h/1st-Bit0 - - <--> X*2 2005h/1st-Bit1 - - <--> X*4 2005h/1st-Bit2 |
Port 2006h-1st Write (VRAM Pointer MSB)
As one might (not) have expected, this does NOT change the VRAM Pointer,
instead, the written value is stored in the corresponding Reload bits (Port
2005h/2000h settings), the VRAM pointer is left unchanged for now.
Port 2006h-2nd Write (VRAM Pointer LSB)
The written value is stored in the VRAM Pointer LSB Bits (and maybe also in
the corresponding Reload bits ?). And, the VRAM Pointer MSB is now loaded
from the corresponding Reload bits (ie. the value from the previous Port
2006h-1st Write is applied now).
Port 2005h-1st Write (Horizontal Scroll Origin, X*1, 0-255)
Port 2005h-2nd Write (Vertical Scroll Origin, Y*1, 0-239)
Port 2000h-Bit0 (Horizontal Name Table Origin, X*256)
Port 2000h-Bit1 (Vertical Name Table Origin, Y*240)
Writing to these registers changes the Reload value bits only, the VRAM
Pointer is left unchanged (except for indirect changes at times when the
Reload value is loaded into the Pointer during rendering).
Full-screen and Mid-frame Scrolling
Simple full-screen scrolling can be implemented by initializing the Reload
value via Ports 2005h and 2000h. Many games change the scroll settings
mid-frame to split the screen into a scrolled and non-scrolled area: The
Horizontal bits can be changed by re-writing the Reload value via Ports 2005h
and 2000h, the vertical bits by re-writing the Pointer value via Port 2006h.
Changing both horizontal and vertical bits is possible by mixed writes to
Port 2005h and 2006h, for example:
[2006h.1st]=(X/256)*4 + (Y/240)*8 [2005h.2nd]=((Y MOD 240) AND C7h) [2005h.1st]=(X AND 07h) [2006h.2nd]=(X AND F8h)/8 + ((Y MOD 240) AND 38h)*4 |
Notes: In that example, most bits are updated twice, once via 2006h and once via 2005h, above shows only the relevant bits, the other bits would be don't care (eg. writing unmasked values to 2005h would be faster, and wouldn't change the functionality). The 1st/2nd-write-flipflop is toggled on each of the four writes, so that above does <first> change 2005h-2nd-write, and <then> 2005h-1st-write.
Pointer Increment/Reload during Rendering
During rendering, A4-A0 is incremented per tile, with carry-out to A10, at
end of HBlank A4-A0 and A10 are reset to the Reload value. "A14-A12" are used
as LSBs of Tile Data address, these bits are incremented per scanline, with
carry-out to tile row A9-A5, the tile row wraps from 29 to 0 with carry-out
to A11.
Note: Initializing the tile row to 30 or 31 will display garbage tiles
(fetched from Attribute table area), in that case the row wraps from 31 to 0,
but without carry-out to A11.
| PPU Tile Memory |
PPU 0000h-0FFFh - Pattern Table 0 (4K) (256 Tiles)
PPU 1000h-1FFFh - Pattern Table 1 (4K) (256 Tiles)
Pattern Table Format
Each pattern table contains 256 tiles. When using both pattern table 0 and 1,
up to 512 tiles can be used for Background and Sprites.
Each tile consists of a 8x8 pixel bitmap with 2bit depth (4 colors). Each
tile occopies 16 bytes, the first 8 bytes contain color bit 0 for each pixel,
the next 8 bytes color bit 1. Each byte defines a row of 8 pixels (MSB left).
Pattern Table Memory
The console does NOT include built-in Pattern Table Memory. Instead, Pattern
tables are located in the cartridge, usually in a separate ROM chip, or (less
often) in a SRAM chip. Cartridges with more than 8K Pattern memory may
contain whatever mapping mechanisms to map the memory into the PPU 8K Pattern
Memory area.
| PPU Background |
PPU 2000h-23FFh - Name Table 0 and Attribute Table 0 (1K)
PPU 2400h-27FFh - Name Table 1 and Attribute Table 1 (1K)
PPU 2800h-2BFFh - Name Table 2 and Attribute Table 2 (1K)
PPU 2C00h-2FFFh - Name Table 3 and Attribute Table 3 (1K)
PPU 3000h-3EFFh - Mirror of 2000h-2EFFh
Name Table Format
Each Name Table occupies 3C0h bytes, containing 8bit tile numbers for 32x30
tiles (256x240 pixels). The tiles are fetched from Pattern Table 0 or 1
(depending on Bit 4 in PPU Control Register 1). Note that NTSC displays may
be unable to display the whole 256x240 pixels, basically the relevant portion
of screen output should be in the <middle> 32x28 tiles (256x224 pixels) see
PPU Dimensions and Timings chapter for more info.
Attribute Table Format
Each Name Table is directly followed by an Attribute Table of 40h bytes,
containing 2bit background palette numbers for each 16x16 pixel field. Each
byte in the Attribute table defines palette numbers for a 32x32 pixel area:
Bit0-1 Palette Number for upperleft 16x16 pixels of the 32x32 area Bit2-3 Palette Number for upperright 16x16 pixels of the 32x32 area Bit4-5 Palette Number for lowerleft 16x16 pixels of the 32x32 area Bit6-7 Palette Number for lowerright 16x16 pixels of the 32x32 area |
Note: Attributes for each 8x1 pixel row are fetched from cartridge bus. The MMC5 Mapper with EXRAM allows to use different palettes for each 8x8 pixel tile, instead of sharing one palette for above 16x16 areas.
Background Scrolling
Scrolling origin is defined by the Name Table selection in Bit0-1 of $2000,
and by offsets in $2005, of which Horizontal offsets may range in 0-255,
vertical offsets in 0-239; values above 239 are considered negative (eg. 248
is -8). The picture wraps to the next Name Table when drawing exceeds the
boundaries of the current Name Table...
Multiple Name Tables
The NES has the capability of addressing up to four Name Tables (NT0-3),
allowing to define backgrounds of up to 512x480 pixels, arranged as such:
Square Horizontal Scroll Vertical Scroll NT0 NT1 NT0 left/right NT1 NT0 above/below NT2 NT2 NT3 NT2 left/right NT3 NT1 above/below NT3 |
However, the NES includes only 2K VRAM, so that not more than two Name Tables can be used (unless the cartridge includes external Name Table memory).
Name Table Mapping/Mirroring
The NES outputs the desired Name Table number (NT0-3) to the cartridge, which
may then respond by selecting one of the two internal 1K RAM blocks (BLK0-1),
or by presenting an external RAM/ROM block (eg. BLK2-3). Examples:
_Name Table____________NT0___NT1___NT2___NT3___Purpose______________ Horizontal Mirroring BLK0 BLK0 BLK1 BLK1 Vertical Scrolling Vertical Mirroring BLK0 BLK1 BLK0 BLK1 Horizontal Scrolling Four-screen BLK0 BLK1 BLK2 BLK3 Four-Way Scrolling |
When using only the internal blocks, the cartridge may use a simple hardwired connection between two pins to select horizontal or vertical mirroring. Also, the cartridge may contain whatever circuits to map Single-Screen or CHR-ROM to whatever addresses dependently or independently of the selected NT number.
Background Clipping
The PPU allows to mask the left 8 pixels of BG, allowing to use horizontal
scrolling with only one Name Table, the 16pix-width palette attribute isn't
fully clipped though. Also, BG could be vertically clipped by software, which
would require accurate timing though. Aside from that, it'd be no problem to
implement four-way scrolling by using only one name table.
| PPU Sprites |
SPR-RAM 00-FF - Sprite Attributes (256 bytes, for 64 sprites / 4 bytes each)
The PPU supports 64 sprites, which can be either 8x8 or 8x16 pixels in size,
only 8 sprites can be displayed per scanline. The sprite Tile bitmaps are
kept within the Pattern Table region of VRAM (which is also used for BG
Tiles).
Sprite-RAM is built-in in the PPU-chip, and can be accessed via I/O ports
only (it is not part of the PPU or CPU memory area). Each four bytes in
SPR-RAM define attributes for one sprite, bytes 0-3 for sprite 0, up to bytes
FCh-FFh for sprite 63.
SPR-RAM Byte 0 - Y Coordinate Minus 1
Vertical Position-1 (FFh,00h..EEh=Scanline 0..239, EFh..FEh=Not displayed) |
The sprites can be moved bottom-offscreen, but cannot be moved top-offscreen.
SPR-RAM Byte 1 - Tile Number
In 8x8 pixel mode (PPU Control Register 1, Bit5=0):
Bit7-0 Specifies 8bit tile number And, Pattern Table selected by Bit 3 in PPU Control Register 1 |
In 8x16 pixel mode (PPU Control Register 1, Bit5=1):
Bit7-1 Upper 7bit of tile number (N=0-127 uses Tiles N*2 and N*2+1) Bit0 Pattern Table Address (0=VRAM 0000h, 1=VRAM 1000h) |
SPR-RAM Byte 2 - Attributes
7 Vertical Flip (0=Normal, 1=Mirror) 6 Horizontal Flip (0=Normal, 1=Mirror) 5 Background Priority (0=Sprite In front of BG, 1=Sprite Behind BG) 4-2 Not used (Always zero when reading from SPR-RAM) 1-0 Sprite Palette (0-3=Sprite Palette 0-3) |
SPR-RAM Byte 3 - X Coordinate
Horizontal Position (00h..FFh) |
Sprites can be moved right-offscreen, and clipping via Port 2001h also allows to move sprites somewhat left-offscreen.
Sprite Priorites
If two or more non-transparent sprite-pixels overlap, then only the sprite
with highest priority is processed. If the sprites background priority bit is
set to "Behind BG", then it will be hidden behind any non-transparent
background pixels.
Sprite 0 = highest priority Sprite 63 = lowest priority |
Mind that the PPU processes ONLY the sprite with highest priority, eg. if a non-transparent pixel of sprite 5 hides "Behind BG", then sprite 6-63 won't be displayed (even if they are "In Front of BG").
Sprite 0 Hit Flag (Collision Check between BG and Sprite 0)
The Hit Flag, Bit 6 of register 2002h, gets set when the cathode ray beam
passes a non-transparent Sprite 0 pixel which is overlapping a
non-transparent BG pixel (regardless the sprites BG priority).
The Hit Flag is automatically reset at the end of the VBlank period, it
cannot be set or reset by software, that means one can detect only one Hit
per frame.
Aside from a normal collision detection, the Hit Flag is also useful to
detect when the cathode ray beam has reached a specific screen location, eg.
to split the picture into a scrolled and non-scrolled section.
Color 1 or color 2 are (NOT) non-nontransparent (?)
| PPU Palettes |
PPU 3F00h-3F1Fh - Background and Sprite Palettes
Palette Memory (25 entries used)
3F00h Background Color (Color 0) 3F01h-3F03h Background Palette 0 (Color 1-3) 3F05h-3F07h Background Palette 1 (Color 1-3) 3F09h-3F0Bh Background Palette 2 (Color 1-3) 3F0Dh-3F0Fh Background Palette 3 (Color 1-3) 3F11h-3F13h Sprite Palette 0 (Color 1-3) 3F15h-3F17h Sprite Palette 1 (Color 1-3) 3F19h-3F1Bh Sprite Palette 2 (Color 1-3) 3F1Dh-3F1Fh Sprite Palette 3 (Color 1-3) |
Palette Gaps and Mirrors
3F04h,3F08h,3F0Ch - Three general purpose 6bit data registers. 3F10h,3F14h,3F18h,3F1Ch - Mirrors of 3F00h,3F04h,3F08h,3F0Ch. 3F20h-3FFFh - Mirrors of 3F00h-3F1Fh. |
Palette Entries
Bit7-6 Not used (contains garbage when reading palette memory) Bit5-4 Luminance (Grayscale) (0-3) Bit3-0 Chrominance (Color) (0-F) |
The Color values are based on the NTSC color-wheel (even on PAL consoles):
|__0__|__1___2___3___4___5___6___7___8___9___A___B___C_|_D__|__E___F__| |White|..Blue..Magenta..Red......Yellow...Green....Blue|Gray| Black | |
Color and Grayscale (0-3) can be combined as such:
Luminance__0Xh_______1Xh__________2Xh_________3Xh___________________ Color 0: Med Gray, Light Gray, White, White Color 1-C: (Dark), (Normal), (Brighter), (Brightest/Pastelized) Color D: Reserved, Black, Dark Gray, Lighter Gray Color E-F: Black, Black, Black, Black |
Some black/white colors are duplictated, one should normally use 0Eh or 0Fh as black. Of the two Light Grays, 3Dh is slightly brighter than 10h. The Reserved color is Blacker-than-black, producing a very low voltage, which some monitors may or may not treat to be a sync signal rather than a color.
Monochrome Television Set (nine different grayshades)
On mono TV sets, Colors 0 and D-F can be used for Black/Gray/White colors as
usually, and Colors 1-C are all displayed as grayshades: 01h-0Ch=Black,
11h-1Ch=Med/Dark Gray, 21h-2Ch=Med/Light Gray, 31h-3Ch=Bright Gray. Intensity
ramp example: 0Eh, 2Dh, 11h, 00h, 21h, 01h, 3Dh, 31h, 30h. Also, the Color
Emphasis bits are somewhat affecting the luminance output, even on mono
television sets.
Monochrome Bit (three different grayshades)
When Port 2001h/Bit0 is set: The lower 4bits of all palette entries are
treated to be zero. That means that only 3 colors can be displayed: Gray,
Light Gray, and White. All other colors cannot be used (even Black and Dark
Gray are disabled). The Color Emphasis bits can be still used (eg. to change
above 3 gray-shades into 3 pastelized green-shades).
Color Emphasis Bits
Port 2001h/Bit7-5 allow to adjust the palette, eg. with setting 001b the
whole picture becomes more green.
000b Normal 001b Green 010b Brown 100b Blue |
To play by the rules, one should reportedly not set more than one of the emphasis bits at once, setting two or more bits may shortcut something inside the PPU, though it doesn't seem to damage the chip.
Border Color and Clipping Colors
The screen border is black, regardless of any palette settings.
The Color 0 setting is displayed when the BG is disabled, when the whole
display is disabled, and when the left BG row is clipped.
VS Unisystem Palette
The VS Unisystem arcade machine uses a different color palette than
NES/Famicom consoles. It seems to support 64 colors, further info is not
available?
PPU Cartridge Bus Note
When software accesses palette RAM via Port 2006h/2007h, the palette address
accessed actually does show up on the PPU address bus, but the PPU's /RD and
/WR signals are not activated (palette memory is located inside of the PPU
chip, not on external VROM/VROM chips).
| PPU Dimensions & Timings |
NTSC/PAL Timings
Item NTSC PAL Video Clock 21.47727MHz 26.601712MHz CPU Clock 1.7897725MHz 1.7734474MHz Clock Divider CPU=Video/12 CPU=Video/15 Cycles/Scanline 113.66; 1364/12 106.53; 1598/15 Total Scanlines 262 (240+22) 312 (240+72) Frame Rate 60.098Hz 53.355Hz |
Visible Screen Resolution
The logical screen resolution processed by the PPU is 256x240 pixels. However
the visible screen resolution is somewhat smaller, due to improper blanking
periods, and eventually due to exceeding the physical dimensions of (NTSC)
displays.
On PAL hardware, the upper 1 scanline, the left 2 pixels, and the right 2
pixels are invisible (displayed as black border). On NTSC hardware, the upper
8 scanlines, and the lower 8 scanlines are often invisible (224 lines
visible), eventually some NTSC screens are hiding only the upper 3 scanlines
(237 lines visible).
To be compatible with all types of displays, output valid 256x240 pixels, but
have the relevant information in the <middle> 240x224 pixels (30x28 tiles)
only.
Synchronizing Software with the Cathode Ray Beam
The PPU sets the VBlank flag in PPU Status Register (and optionally produces
an NMI) once per frame. It doesn't support scanline interrupts, or a current
scanline number register, which is making it a bit difficult to access PPU
registers at specific Cathode Ray Beam locations (for example, to split the
the screen into two sections with different colors or scroll offsets).
However, a couple of methods could be used for that purpose:
1) Delay Loops synchronized with NMI (badly wasting CPU time) or using
meaningful code with fixed non-conditional execution time instead delays.
2) Producing a "Sprite 0 Hit", or a "More Than 8 Sprites Per Scanline"
situation at specific screen location (which sets corresponding flag in
PPU Status Register, one cannot reset the flag manually, so either works
only once per frame)
3) Using PCM Sound IRQs as Timer (synchronized with NMI)
4) Using external Timers (contained in some Cartridge Mappers)
|
The APU also contains a so-called "Frame" counter - that counter is NOT physically synchronized with the PPU, and it doesn't even match the exact number of clock cycles per frame. There's a limited chance that one could program it to produce an IRQ at a specific screen location (and to resynchronize it for the next frame).
More detailed Timing Info
PPU 2C02 Timings
| PPU 2C02 Timings |
PPU base timing - NTSC
the 21.48 MHz signal is divided by 4 to get 5.37 MHz, and is used as the
smallest unit of timing in the PPU. All following references to PPU clock
cycle (abbr. "cc") timing in this document will be in respect to this timing
base, unless otherwise indicated.
- Pixels are rendered at the same rate as the base PPU clock.
In other words, 1 clock cycle= 1 pixel.
- One frame consists of 262 scanlines.
This equals 341*262 PPU cc's per frame (divide by 3 for # of CPU cc's).
- 341 PPU cc's make up the time of a typical scanline (or 341/3 CPU cc's).
|
All PPU memory access cycles are 2 clocks long, and can be made back-to-back (typically done during rendering). Here's how the access breaks down:
At the beginning of the access cycle, PPU address lines 8..13 are updated
with the target address. This data remains here until the next time an access
cycle occurs.
Miscellanious PPU info
- Reading from $2002 clears the vblank flag (bit 7), and resets the
internal $2005/6 flip-flop. Writes here have no effect.
- $2002.5 and $2002.6 after being set, stay that way for the first 20
scanlines of the new frame, relative to the VINT.
- Pin /VBL on the 2C02 is the logical NAND between 2002.7 and 2000.7.
|
Frame rendering details
The following describes the PPU's status during all 262 scanlines of a frame.
Any scanlines where work is done (like image rendering), consists of the
steps which will be described in the next section.
0..19: Starting at the instant the VINT flag is pulled down (when a NMI is
generated), 20 scanlines make up the period of time on the PPU which I like
to call the VINT period. During this time, the PPU makes no access to it's
external memory (i.e. name / pattern tables, etc.).
20: After 20 scanlines worth of time go by (since the VINT flag was set), the
PPU starts to render scanlines. This first scanline is a dummy one; although
it will access it's external memory in the same sequence it would for drawing
a valid scanline, no on-screen pixels are rendered during this time, making
the fetched background data immaterial. Both horizontal *and* vertical scroll
counters are updated (presumably) at cc offset 256 in this scanline. Other
than that, the operation of this scanline is identical to any other. The
primary reason this scanline exists is to start the object render pipeline,
since it takes 256 cc's worth of time to determine which objects are in range
or not for any particular scanline.
21..260: after rendering 1 dummy scanline, the PPU starts to render the
actual data to be displayed on the screen. This is done for 240 scanlines, of
course.
261: after the very last rendered scanline finishes, the PPU does nothing for
1 scanline (i.e. the programmer gets screwed out of perfectly good VINT
time). When this scanline finishes, the VINT flag is set, and the process of
drawing lines starts all over again.
Scanline rendering details
As explained before, external PPU memory can be accessed every 2 cc's. With
341 cc's per scanline, this gives the PPU enough time to make 170 memory
accesses per scanline (and it uses all of them!). After the 170th fetch, the
PPU does nothing for 1 clock cycle. Remember that a single pixel is rendered
every clock cycle.
Note that the PPU fetches an attribute table byte for every 8 sequential
horizontal pixels it draws. This essentially limits the PPU's color area (the
area of pixels which are forced to use the same 3-color palette) to only 8
horizontally sequential pixels.
Memory fetch phase 1 thru 128 - BG Fetch
Fetches 4x32 bytes; one Name Table entry, one Attribute Table entry, and two
Pattern Table bytes; for 3rd..34th tile in scanline (33th tile may be parts
visible if BG scrolled, 34th is never visible). From the time of the Name
Table fetch, it takes (16-n) clock cycles until the first pixel of the
fetched tile is processed (drawn on screen, unless being covered by a
Sprite-pixel, and eventually setting the Hit Flag) (n=0..7, horizontal scroll
offset).
Simultaneously with above BG fetch, the PPU pre-processes SPR-RAM for the
NEXT scanline by searching for Sprite Y-cooridnates that are visible in that
scanline, only the first eight matches will be recursed, if the search finds
additional matching entries then bit5 of $2002 will get set to indicate that
one or more entries have been ignored.
Memory fetch phase 129 thru 160 - Sprite Fetch
Fetches 4x8 bytes; two dummy Name Table entris, and two Pattern Table bytes;
for 1st..8th sprite in NEXT scanline (fetches dummy patterns if the scanline
contains less than 8 sprites).
Memory fetch phase 161 thru 168 - BG Fetch
Fetches 4x2 bytes; one Name Table entry, one Attribute Table entry, and two
Pattern Table bytes; for 1st..2nd tile in NEXT scanline.
Memory fetch phase 169 thru 170 (and a half) - Padding
Fetches 2 bytes; two dummy reads from the Name Table address of the 3rd tile
in next scanline. After that fetches, the PPU rests for one "dead" cycle here
(or the equivelant of 1/2 memory access cycle) before repeating the whole
pixel/scanline rendering process. Scanline 20 is the only scanline that has
variable length, on every odd frame, this scanline is only 340 cycles (the
dead cycle at the end is removed). This is done to cause a shift in the NTSC
colorburst phase.
| Audio Processing Unit (APU) |
APU Channel 1-4 Register 0 (Volume/Decay)
APU Channel 1-4 Register 1 (Sweep)
APU Channel 1-4 Register 2 (Frequency)
APU Channel 1-4 Register 3 (Length)
APU Channel 5 - DMC Sound
APU Control and Status Registers
APU 4-bit DAC
APU Various
APU External Sound Channels
Controllers - Microphone
Based on "2A03 technical reference by Brad Taylor" (1st release, April 2004).
| APU Channel 1-4 Register 0 (Volume/Decay) |
4000h - APU Volume/Decay Channel 1 (Rectangle)
4004h - APU Volume/Decay Channel 2 (Rectangle)
400Ch - APU Volume/Decay Channel 4 (Noise)
0-3 Volume / Envelope decay rate
When Bit4=1: Volume (0=Silent/None..F=Loud/Max)
When Bit4=0: Envelope decay rate, NTSC=240Hz/(N+1), PAL=192Hz/(N+1)
4 Envelope decay disable (0=Envelope/Decay, 1=Fixed Volume)
5 Length counter clock disable / Envelope decay looping enable
When Bit4=1: length counter clock disable
When Bit4=0: envelope decay looping enable
0: Disable Looping, stay at 0 on end of decay [ \_____ ]
1: Enable Looping, restart decay at F [ \\\\\\ ]
(Does this still affect Length counter clock disable ?)
6-7 Duty cycle type (unused on noise channel)
0 [--______________] 12.5% Whereas,
1 [----____________] 25.0% [_] = LOW (zero) (0)
2 [--------________] 50.0% [-] = HIGH (volume/decay) (0..F)
3 [------------____] 75.0% Noise randomly outputs LOW or HIGH
|
The Duty Cycle counter is reset when the length counter of the same channel is written to (via $4003/$4007).
Initial Decay Volume:
Only a write out to $4003/$4007/$400F will reset the current envelope decay
counter to a known state (to $F, the maximum volume level) for the
appropriate channel's envelope decay hardware. Otherwise, the envelope decay
counter is always counting down (by 1) at the frequency currently contained
in the volume / envelope decay rate bits (even when envelope decays are
disabled by setting bit 4), except when the envelope decay counter contains a
value of 0, and envelope decay looping (bit 5) is disabled (0).
4008h - APU Linear Counter Channel 3 (Triangle)
0-6 linear counter load register 7 length counter clock disable / linear counter start |
Linear counter incremented-or-decremented? at NTSC=240Hz, PAL=192Hz, same purpose, but higher resolution than length counter, so Triangle channel is ALWAYS using either linear-counter or length-counter, and cannot be used with both counters disabled?
The Triangle channel does not have a variable volume, nor variable duty
cycle. Instead, it produces the following fixed 32-step output level stream:
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,F,E,D,C,B,A,9,8,7,6,5,4,3,2,1,0 |
On 2A03 reset, the stream starts at 0. The stream will be halted (at the current position) whenever the Triangle channel's length or linear counter contains a count of 0, and will continue at whatever old position when it is restarted.
| APU Channel 1-4 Register 1 (Sweep) |
4001h - APU Sweep Channel 1 (Rectangle)
4005h - APU Sweep Channel 2 (Rectangle)
0-2 Sweep right shift amount (S=0..7) 3 Sweep Direction (0=[+]Increase, 1=[-]Decrease) 4-6 Sweep update rate (N=0..7), NTSC=120Hz/(N+1), PAL=96Hz/(N+1) 7 Sweep enable (0=Disable, 1=Enable) |
At specified Update Rate, the 11bit Wavelength will be modified as such:
Wavelength = Wavelength +/- (Wavelength SHR S) (For Channel 1 Decrease only: minus an additional 1) (Ie. in Decrease mode: Channel 1 uses NOT, Channel 2 uses NEG) |
Wavelength register will be updated only if all 3 of these conditions are met:
Bit 7 is set (sweeping enabled) The shift value (which is S in the formula) does not equal to 0 The channel's length counter contains a non-zero value |
Sweep end: The channel gets silenced, and sweep clock is halted, when:
1) current 11bit wavelength value is less than 008h 2) new 11bit wavelength would become greater than 7FFh |
Note that these conditions pertain regardless of any sweep refresh rate values, or if sweeping is enabled/disabled (via Bit7).
4009h - APU N/A Channel 3 (Triangle)
400Dh - APU N/A Channel 4 (Noise)
0-7 Unused (No Sweep support for these channels) |
| APU Channel 1-4 Register 2 (Frequency) |
4002h - APU Frequency Channel 1 (Rectangle)
4006h - APU Frequency Channel 2 (Rectangle)
400Ah - APU Frequency Channel 3 (Triangle)
0-7 Lower 8 bits of wavelength (upper 3 bits in Register 3) |
F = 1.79MHz/(N+1)/16 for Rectangle channels
F = 1.79MHz/(N+1)/32 for Triangle channel
400Eh - APU Frequency Channel 4 (Noise)
0-3 Noise frequency, F=1.79MHz/2/(N+1)
Value 0..F corresponds to following 11bit clock cycle value:
N=002,004,008,010,020,030,040,050,065,07F,0BE,0FE,17D,1FC,3F9,7F2
4-6 Unused
7 Random number type generation (0=32767 bits, 1=93 bits)
|
The random number generator consists of a 15bit shift register. The MSB (Bit14) is output/inverted (1=Low/Zero, 0=High/Decay/Volume). At the specified frequency, Bit14 is XORed with Bit13 (32767-bit mode) or with Bit8 (93-bit mode), the register is then shifted to the left, with the result of the XOR operation shifted-in to Bit0.
On 2A03 reset, this shift register is loaded with a value of 1.
Not sure if it is reset when switching from 32767-bit mode to 93-bit mode? If
it isn't reset then 93-bit mode will act unstable: produce different 93-bit
patterns, or even a 31-bit pattern, depending on old shift register content.
| APU Channel 1-4 Register 3 (Length) |
4003h - APU Length Channel 1 (Rectangle)
4007h - APU Length Channel 2 (Rectangle)
400Bh - APU Length Channel 3 (Triangle)
400Fh - APU Length Channel 4 (Noise)
Writing to the length registers restarts the length (obviously), and also
restarts the duty cycle (channel 1,2 only), and restarts the decay volume
(channel 1,2,4 only).
2-0 Upper 3 bits of wavelength (unused on noise channel) 7-3 Length counter load register (5bit value, see below) |
The above 5bit value is translated to the actual 7bit counter value as such:
Bit3=0 and Bit7=0 (Dividers matched for use with PAL/50Hz)
Bit6-4 (0..7 = 05h,0Ah,14h,28h,50h,1Eh,07h,0Dh)
Bit3=0 and Bit7=1 (Dividers matched for use with NTSC/60Hz)
Bit6-4 (0..7 = 06h,0Ch,18h,30h,60h,24h,08h,10h)
Bit3=1 (General Fixed Dividers)
Bit7-4 (0..F = 7Fh,01h..0Fh)
|
The 7bit counter value is decremented once per frame (PAL=48Hz, or NTSC=60Hz) the counter and sound output are stopped when reaching a value of zero. The counter can be paused (and restarted at current location) by Length Counter Clock Disabled bit in Register 0.
| APU Channel 5 - DMC Sound |
4010h - DMC Play mode and DMA frequency
7 IRQ Enable, when Length=0 AND Loop=Disabled (0=Disable, 1=Enable)
DMC IRQs can be acknowledged by writing 0 to Bit7 of 4010h, or
by writing any value to 4015h
6 Loop when reaching Length=0 (0=Stop, 1=Loop)
In looped mode, the sample block is restarted by reloading the
DMA Start Address and Length values, IRQs are not generated.
5-4 Appear to be unused
3-0 DMC frequency control. For values 0-F, number of cycles/samplebyte are:
D60,BE0,AA0,A00,8F0,7F0,710,6B0,5F0,500,470,400,350,2A8,240,1B0
|
Cycles/samplebit is 8 times less (faster) than cycles/samplebyte.
4011h - DMC Delta counter load register
7 Appears to be unused 6-1 MSBs of 7bit DAC (6bit "Delta Counter") 0 LSB of 7bit DAC |
Used to initialize the Delta Counter (for DMC usage), or to output 7bit data directly (for PCM usage). Another use of this register has been to somewhat control the volume of the Triangle & Noise sound channel outputs. Please see NESSOUND.TXT for more information.
4012h - DMC address load register
Specifies the DMA Start Address. The Start Address is loaded to the actual
DMA pointer, when the DMC is activated from an inactive state, or when
restarting looped playback.
7-0 DMA Start Address for DMC (Address = C000h+N*40h) |
The DMA pointer is 15 bits in size, and wraps from FFFFh to 8000h (not C000h).
4013h - DMC length register
7-0 DMA Length DMC (Length = N*10h+1 Bytes = N*80h+8 Bits) |
When it arrives at 0, the DMC will take action(s) based on the 2 MSB of $4010. This counter will be loaded with the current calculated address value of $4013 when the DMC is activated from an inactive state.
Usage as Delta Modulation Channel (DMC) with Direct Memory Access (DMA)
This method uses 1-bit samples, processed at the specified sample-bit-rate,
1 = Increment Delta counter by 1 (unless result would be greater than 3Fh) 0 = Decrement Delta counter by 1 (unless result would be less than 0) |
Every eight sample-bits, the DMC will halt the CPU for 2 clock cycles to retrieve the next sample-byte per DMA, each sample byte is processed bit-by-bit (LSB first).
Usage as Pulse Code Modulation (PCM) Channel
Alternately, 7bit samples can be written directly to the DAC.
Advantages are that all 7bit can be used (instead only the upper six Delta
bits), and that the DAC can be directly changed from one value to any other
value (which would take up to 64 increment/decrement steps in DMC mode).
Disadvantages are that it requires exact software timings and more CPU load
than the DMA method.
No idea if it is required to "enable" the DMC channel (eg. by outputting a
looped dummy 55h sample byte) in order to use PCM ?
On 2A03 reset, the DMC's IRQ flag is cleared (disabled), and the [DMC]
channel is disabled. On 2A03 reset, all 7 used bits of $4011 are reset to 0.
| APU Control and Status Registers |
4015h - DMC/IRQ/length counter status/channel enable register
0 Status/Enable rectangle wave channel 1 1 Status/Enable rectangle wave channel 2 2 Status/Enable triangle wave channel 3 3 Status/Enable noise channel 4 4 Status/Enable DMC channel 5 5 Not used (returns garbage on reading) 6 Frame IRQ status (active when set) 7 DMC's IRQ status (active when set) |
Reading Bit4-0 returns 0 for a zero count status in the length counter (channel's sound is disabled), and 1 for a non-zero status. Reading Bit7-6 returns IRQ status flags.
Writing to Bit4-0: Writing 0 forces to disable the channel, it will get
stopped and become silent (as if its length counter has reached 0), writing 1
de-activates the forced-stop (without changing the length counter, playback
continues at whatever value have been in the length counter).
Writing to Bit7-5: Unknown.
DMC IRQs are acknowledged by WRITING any value to 4015h.
Frame IRQs are acknowledged by READING from 4015h.
Note that all 5 writable bits in 4015h will be set to 0 upon 2A03 reset.
4017h - APU Low frequency timer control (W)
Any write to $4017 resets both the frame counter, and the clock divider.
Sometimes, games will write to this register in order to synchronize the
sound hardware's internal timing, to the sound routine's timing (usually tied
into the NMI code). The frame IRQ frequency is slightly smaller than the
PPU's vertical retrace frequency, so you can see why games would desire this
syncronization.
bit6: Frame IRQ Disable (0=Enable Frame IRQ, 1=Disable Frame IRQ) bit7: Frame Rate Select (0=NTSC=60Hz=240Hz/4, 1=PAL=48Hz=240Hz/5) |
On 2A03 reset, Bit6-7 will be cleared. That means that Frame IRQs are enabled by default (though usually not executed since the CPUs IRQ-Disable-Flag is set on reset).
Frame IRQs are acknowledged by reading from 4015h.
Frame Counter
Several audio timings are referred to as "Frames" and "PAL" and "NTSC",
! These timings are NOT physically related to actual PPU VBlank/NMI timings ! |
The Audio "Frame" counter can be switched into "PAL" or "NTSC" mode by software - regardless of whether the game does run on a PAL/NTSC console. Audio-frames may be (more or less) synchronized with video-frames by chosing PAL/NTSC audio-mode matching to PAL/NTSC console type respectively.
The frame counter is based on a 240Hz signal which is gained from dividing
the 1.78Mhz PHI2 clock edges (2*1.78M edges/second) by 14915. In PAL Mode
(4017h Bit7=1), the 240Hz signal is divided by 1.25 (by simply leaving out
each fifth clock pulse), resulting in a somewhat dirty 192Hz signal. This
PAL/NTSC adjustment mechanism counts through 4 or 5 steps, producing output
as such:
0/NTSC: 4,0,1,2,3,0,1,2,3,0,1,2,3 | 1/PAL: 0,1,2,3,4,0,1,2,3,4,0,1,2,3,4 240Hz: __-_-_-_-_-_-_-_-_-_-_-_- | 192Hz: -_-_-_-___-_-_-_-___-_-_-_-__ 120Hz: ____-___-___-___-___-___- | 96Hz: __-___-_____-___-_____-___-__ 60Hz: (above somehow div by 2) | 48Hz: (above somehow divided by 2) |
Frame Counter is reset on writing to 4017h, and does then restart sequences as shown above (in NTSC mode starting with a skipped step, whilst directly starting with a non-skipped step in PAL mode).
Linear counter (triangle) and envelope decay counters (rectangle/noise) are
clocked by 240Hz/192Hz. Frequency sweep (rectangle) clocked by 120Hz/96Hz.
Length counters (all channels) and Frame IRQ clocked by 60Hz/48Hz.
4014h - SPR-RAM DMA
Sprite RAM DMA Function contained in 2A03 chip. See PPU description.
4016h - Write
Three bit general purpose output latch contained in 2A03 chip.
Used to strobe joysticks. See Controllers chapter for more info.
4016h/4017h - Read
The 2A03 chip does not actually contain read-able registers at these
addresses, however, it does output read-request signals for these addresses,
which are used to activate on-board joystick inputs.
See Controllers chapter for more info.
Note: 4015h is the only R/W register in the 4000h-4017h area, all other
registers in this area are write-only, and do not respond to read cycles
(except for the external read-able 4016h/4017h registers).
| APU 4-bit DAC |
Channel 1-4 are (each) using a standard 4-bit DAC with 16 steps of output
voltage resolution. On the 2A03, rectangle wave 1 & 2 are mixed together, and
are available via pin 1. Triangle, noise, and DMC are available on pin 2.
Signals are then merged via 20KOhm (pin 1) and 12KOhm (pin2), respectively,
rectangle channels have different output levels than equivalent volume
settings on triangle/noise channels?
The output waveforms have some linear asymmetry (the desired output voltage
would increase on a linear scale, the actual outputted voltage increases less
and less each step).
The side effect of this is that the DMC's 7-bit DAC port ($4011) is able to
indirectly control the volume (somewhat) of both triangle & noise channels.
When $4011=0, triangle & noise volume outputs are at maximum. When $4011=7F,
triangle & noise channel outputs operate at only 57% total volume. A few
games actually take advantage of this "volume" feature, and write values to
$4011 in order to regulate the amplitude of the triangle wave channel's
output.
Forced Zero Volume:
When hardware in the channel wants to disable it's sound output (like the
length counter, or sweep unit).
| APU Various |
After 2A03 reset, the sound channels are unavailable for playback during the
first 2048 CPU clocks.
The rectangle channel(s) frequency in the range of 54.6 Hz to 12.4 KHz.
The triangle wave channel range of 27.3 Hz to 55.9 KHz.
The random wavelength channel range anywhere from 29.3 Hz to 447 KHz.
RP2A03E quirk
I have been informed that revisions of the 2A03 before "F" actually lacked
support for the 93-bit looped noise playback mode. While the Famicom's 2A03
went through 4 revisions (E..H), I think that only one was ever used for the
front loading NES: "G". Other differences between 2A03 revisions are
unknown. Is that Quirk True and Confirmed ?
| APU External Sound Channels |
The Famicom 60-pin cartridge slot includes a SND_IN pin, allowing external
sound controllers (as included in some Cartridge Mappers, and in Famicom Disk
System) to produce additional sound channels which are merged with the normal
APU channels:
Mapper 5: MMC5 - BANKING, IRQ, SOUND, VIDEO, MULTIPLY, etc.
Mapper 19: Namcot 106 - PRG/8K, VROM/1K/VRAM, IRQ, SOUND
Mapper 20: Disk System - PRG RAM, BIOS, DISK, IRQ, SOUND
Mapper 24: Konami VRC6A - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
Mapper 26: Konami VRC6B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
Mapper 85: Konami VRC7A/B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
However, the NES 72-pin cartridge slot DOES NOT include a SND_IN pin, even
though it does have more (more or less unused) pins than Famicom.
| Controllers |
Controllers - I/O Ports
Controllers - Pin-Outs
Controllers - Joypads
Controllers - Zapper
Controllers - Paddles
Controllers - Keyboard
Controllers - Power Pad
Controllers - Microphone
Controllers - Reset Button
Controllers - Arcade Machines
R.O.B (Robotic Operating Buddy), a plastic robot used by Gyromite and
Stack-up.
| Controllers - I/O Ports |
Port 4016h-4017h control 3 general purpose outputs (OUT0/1/2), plus 2 clock
outputs (PORT0/1-CLK), and several inputs (number of inputs varies depending
on the console type), all inputs are inverted inside of the console, ie. LOW
arrives as "1" at the CPU.
4016h - Joypad Output Register (W)
2-0 OUT2-0 Expansion Port Outputs 0 OUT0 NES/Famicom: Joypad 1+2 Strobe (for BOTH joypads) |
4016h - Joypad Input Register 0 (R)
Bit Name NES Famicom Purpose 7-5 N/A Not used (undefined) Not used (undefined) - 4 PORT0-4 Expansion/Gameport Not used (undefined) Zapper 1 Button 3 PORT0-3 Expansion/Gameport Not used (undefined) Zapper 1 Light 2 PORT0-2 Expansion Microphone Input Microphone 1 PORT0-1 Expansion Expansion Exp. 0 PORT0-0 Expansion/Gameport Joypad Joypad 1 |
Reading from 4016h generates a PORT0-CLK signal (used to clock joypads).
4017h - Joypad Input Register 1 (R)
Bit Name NES Famicom Purpose 7-5 N/A Not used (undefined) Not used (undefined) - 4 PORT1-4 Expansion/Gameport Expansion Zapper 2 Button 3 PORT1-3 Expansion/Gameport Expansion Zapper 2 Light 2 PORT1-2 Expansion Expansion Exp. 1 PORT1-1 Expansion Expansion Exp. 0 PORT1-0 Expansion/Gameport Expansion/Joypad Joypad 2 |
Reading from 4017h generates a PORT1-CLK signal (used to clock joypads).
4017h - APU Low frequency timer control (W)
Not joypad/expansion related. See APU chapter for more info.
For info about the "Not used (undefined)" bits, see:
Unpredictable Things
| Controllers - Pin-Outs |
Controller ports - NES (and newer Famicom models) - male, front side
Pin Dir Player 1 Player 2 Expl. _________ 1 Out GND GND Ground | 4 3 2 1 | 2 Out PORT0-CLK PORT1-CLK Joystick Clock (CPU Port Read) |_7_6_5__/ 3 Out OUT0 OUT0 Joystick Serial-Start 4 In PORT0-0 PORT1-0 Joystick Serial-Data _________ 5 Out +5VDC +5VDC Supply | 4 3 2 1 | 6 In PORT0-3 PORT1-3 Zapper Light |_7_6_5__/ 7 In PORT0-4 PORT1-4 Zapper Button |
All controller inputs are inverted inside of the console, LOW arrives as "1".
Note: Older Famicom consoles do not include controller ports, instead the
joypad cables are directly attached to the console (without plugs/sockets).
Famicom Expansion Port (standard db15, female, front side)
Included in both older and newer Famicom consoles, not in NES consoles.
1 Out GND ------------------------ 2 Out SOUND OUT | 8 7 6 5 4 3 2 1 | 3 I/O /IRQ \ 15 14 13 12 11 10 9 / 4 In port1-D4 (zapper button) -------------------- 5 In port1-D3 (zapper light) 6 In port1-D2 7 In port1-D1 (joystick 4 serial input) (paddle ADC serial input) 8 In port1-D0 (joystick 2 serial input) 9 Out port1-CLK (joystick 2+4 clock read) 10 Out OUT2 11 Out OUT1 12 Out OUT0 (joystick 1+2+3+4 start) 13 In port0-D1 (joystick 3 serial input) (paddle button input) 14 Out port0-CLK (joystick 1+3 clock read) 15 Out +5V |
Used to connect a 3rd and 4th joystick, and various other expansion hardware.
Keep in mind that older Famicom Joypads cannot be disconnected, so the input
at Pin 8 may be disturbed by joypad 2 signals.
Note: Joypads/PowerPads/etc are normally using standard 4021 parallel-in
serial-out shift registers.
| Controllers - Joypads |
Joypads (or Joysticks)
Each joypad includes an 8bit shift register, set Port 4016h/Bit0=1 to reload
the button states into the shift registers of both joypads, then reset Port
4016h/Bit0=0 to disable the shift reload (otherwise all further reads would
be stuck to the 1st bit, ie. Button A). Joypad data can be then read from bit
0 of 4016h (joypad 1) and/or bit 0 of 4017h (joypad 2) as serial bitstream of
8bit length, ordered as follows:
A, B, SELECT, START, UP, DOWN, LEFT, RIGHT |
The console automatically sends a clock pulse to the Joypad 1 shift register after each read from 4016h (and to joypad 2 after read from 4017h). There are no timing restrictions, joypads can be handled as fast, or as slow, as desired. Received bits are 1=LOW=Pressed/Moved, 0=HIGH=Released. 1-Bits (LOW) are returned after the 8th bit has been received. 0-Bits (HIGH) are returned if no controller connected to the console.
Note that older Famicom controllers include Select & Start buttons only on
joypad 1 - joypad 2 probably returns unused dummy bits instead.
NES Four-player devices (Satellite and Four Score)
Used by Tengen's "Gauntlet II", and Nintendo's "RC Pro Am 2". The device is
connected to both of the consoles two controller ports, and up to four
controllers can be connected to the device.
The device is accessed much like normal joypads, except that the returned
bitstream consist of 24 bits instead of normal 8 bits:
write "1-then-0" to (4016h) (that only once, for all 24 bits) read 1st 8 bits: controller 1 (4016h) / controller 2 (4017h) (as normal) read 2nd 8 bits: controller 3 (4016h) / controller 4 (4017h) (new ports) read 3rd 8 bits: 0,0,0,1,0,0,0,0 (4016h) / 0,0,1,0,0,0,0,0 (4017h) (ID codes) |
The ID codes can be used to detect if the 4-player adapter is connected (used by RC Pro Am 2, not used by Gauntlet II). Otherwise the ID field typically contains all ones (normal/single controller), or all zeros (no controller connected at all).
Famicom Four-player device (Two extra joypads at Expansion Port)
Older Famicom consoles have 2 "built-in" joypads, additional 2 joypads can be
connected to the expansion port. Used by Nekketsu Kakutou Densetsu? The
procedure for reading Famicom 4-player data is similar as for 2-player data:
As normal, write "1-then-0" to 4016h, then read 8 times from 4016h, that
simultaneously receives data for two pads, Bit 0 for joypad 1, and
additionally Bit 1 for joypad 3. Respectively, Bit 0 and 1 of 4017h are for
pad 2 and 4.
Joypad Layout
___________________________________ | _ | | _| |_ Nintendo | | |_ _| SELECT START | | |_| (==) (==) ( B ) ( A ) | |___________________________________| |
Jump and Run Games conventionally use A=Jump, B=Fire.
| Controllers - Zapper |
Zapper (Light Gun) Ports / Connection
Zapper state can be obtained by reading Bit4-5 of Port 4017h and/or 4016h.
Bit4 Trigger state of the gun (0=Released, 1=Pulled/Pressed) Bit3 State of the gun sight (0=None, 1=Light detected) |
Famicom Zapper connected to Famicom Expansion Port (Inputs at 4017h).
NES Zappers connected to 1st and/or 2nd Joypad Port (Inputs at 4016h, 4017h).
Many NES games may default to use 2nd Joypad Port because Famicom uses 4017h.
Control Methods
The light detection flag gets set when sensing light emission from the
display, ie. when the cathode ray beam outputs a bright color (preferably
white) at the location where the gun is pointed to.
Most video controllers are latching the current cathode ray beam coordinates
at the time when the light detection flag gets set - that's not supported by
the NES/Famicom video controller - it could be eventually implemented by
software, ie. by counting the number of clock cycles between vblank and light
detection.
Otherwise, the following trick can be used: Output a black picture, with a
white field at the desired target location, wait for 1-2 frames, then check
the light detection flag to see if the zapper was pointed to the target area
or not. The downside is that the normal picture cannot be displayed during
that time, so one should check the zapper position only when necessary, ie.
typically only at the moment when the trigger gets pulled.
Unknown if/when/how the light detection flag gets reset?
| Controllers - Paddles |
The Paddle consists of a potentiometer (can be turned left/right by about 270
degrees), and a push button. The potentiometer is connected to an Analogue to
Digital Converter, that ADC data is then sent to the console in serial via
shift register. Taito's "Arkanoid" uses a paddle as it's primary controller.
The paddle position is read via D1 of $4017; the read data is inverted (0=1,
1=0). The first value read is the MSB, and the 8th value read is (obviously)
the LSB. Valid value ranges are 98 to 242, where 98 represents the paddle
being turned completely counter-clockwise.
For example, if %01101011 is read, the value would be NOT'd, making %10010100
which is 146. The paddle also contains one button, which is read via D1 of
$4016. A value of 1 specifies that the button is being pressed.
Is that Famicom-Expansion-Port only ?
| Controllers - Keyboard |
Keyboard with 72 Keys, and tape read/write port, connected to 15-pin Famicom
Expansion port. Used by Famicom BASIC. Also, the Study and Game 32-in-1 and
Education 18-in-1 cartridges use an identical protocol, but with different
keyboard matrix.
Keyboard Access Pseudo Code
[4016h]=05h:WAIT(16clks) ;reset (force row 0)
FOR i=0 TO 8 ;loop 9 rows
[4016h]=04h:WAIT(56clks) ;request LSB of NEXT row
Row[i]=(([4017h] SHR 1) AND 0Fh) ;read LSB
[4016h]=06h:WAIT(56clks) ;request MSB of SAME row
Row[i]=(([4017h] SHL 3) AND F0h)+Row[i] ;read MSB
NEXT ;loop next
|
Column 0-7 are then in Bit0-7 of each row. Bits are 0=Pressed, 1=Released (unlike for most other NES/Famicom controllers, which are 1=Pressed).
When reading more than 9 rows, the 10th read (row 9) returns garbage data,
and then starts over at row 0.
Famicom Keyboard Matrix
Row Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 0 F8 RETURN [ ] KANA R-SHFT \(Yen) STOP 1 F7 @ : ; _ / - ^ 2 F6 O L K . , P 0 3 F5 I U J M N 9 8 4 F4 Y G H B V 7 6 5 F3 T R D F C 5 4 6 F2 W S A X Z E 3 7 F1 ESC Q CTRL L-SHFT GRPH 1 2 8 CLR UP RIGHT LEFT DOWN SPACE DEL INS |
Famicom Keyboard Layout
________________________________________________ | F1 F2 F3 F4 F5 F6 F7 F8 | | 1 2 3 4 5 6 7 8 9 0 - ^ \ STOP | | ESC Q W E R T Y U I O P @ [ ENTER CLR INS DEL | | CTRL A S D F G H J K L ; : ] KANA UP | | SHIFT Z X C V B N M , . / _ SHIFT LEFT RIGHT | |______GRPH____SPACE____________________DOWN_____| |
32-in-1 Study and Game / Education Keyboard Matrix
Row Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 0 4 G F C F2 E 5 V 1 2 D S END F1 W 3 X 2 INS BS PGDN RIGHT F8 PGUP ESC HOME 3 9 I L , F5 O 0 . 4 ] ENTER UP LEFT F7 [ \ DOWN 5 Q CAPS Z Pa ESC A 1 CTRL 6 7 Y K M F4 U 8 J 7 - ; ' / F6 P = SHIFT 8 T H N SPACE F3 R 6 B |
The 32-in-1 menu also checks Bit4 in Row 9, if that bit is zero then it does additionally read row 0Ah..0Ch. Aside from the menu, most or all games in the 32-in-1 cartridge don't seem to use that extra rows though.
32-in-1 Study and Game Keyboard Layout (as shown in Typing School I)
____________________________________________________________ | ESC F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 Pa. Br Nu Re. | | ~ 1 2 3 4 5 6 7 8 9 0 - + BS HOME | | TAB Q W E R T Y U I O P [ ] \ END | | CAPS A S D F G H J K L ; ' ENTER PGUP | | SHIFT Z X C V B N M , . / SHIFT UP PGDN | |_###_CTRL_ALT_##_[______SPACE______]_ALT_INS_DEL_LT_DN_RIGH_| |
Keyboard I/O Signals
OUT.0 Keyboard Strobe/Reset (0=Normal, 1=Initialize) OUT.1 Keyboard Clock (0=LSB, 1=MSB) (1-to-0=Next Row) OUT.2 Tape Output? (Should be 1 when accessing Keyboard) PORT0-1 Tape Input PORT1-4..1 Keyboard Input Bit3..0 (either MSB or LSB of current row) |
| Controllers - Power Pad |
The Power Pad or Family Trainer is a device made by Bandai/Nintendo
(1987/1988) which serves as an "exercising fun center" for the whole family.
That is, a large (1x1 meters) vinyl mat with 12 touch-sensitive areas, or
actually step-sensitive since it's intended to be put on the floor. The mat
has two sides, with different patterns drawn on each side.
Used by Athletic World, World Class Track Meet (originally called Stadium
Events), Super Team Games, Street Cop, Dance Aerobics, Short Order/Eggsplode.
Power Pad Layout (Side A and Side B)
_____/--A--\_____ _____/--B--\_____ | | | | | (b) (b) | | (1) (2) (3) (4) | | (b) (r) (r) (b) | | (5) (6) (7) (8) | | (b) (b) | | (9) (A) (B) (C) | |_________________| |_________________| |
Side A has 2 red fields, 6 blue fields, and 4 hidden fields.
Side B has 12 fields, numbered 1..12 (referred to as 1-C hex, in this
document), the left fields (1,2,5,6,9,A) are blue, the other are red.
Power Pad Connection / Access
Famicom version is connected to Expansion Port (inputs at 4017h), NES version
can be connected to Joypad Port 1 or 2 (inputs at 4016h or 4017h, or both
with two pads). Many NES games may default to use Joypad Port 2, for Famicom
compatibility, also Port 1 is often used for menu selection via joypad. To
read the button states:
Output 1-then-0 to Bit0 of Port 4016h Read eight times from Port 4017h (and/or 4016h on NES) |
Each read receives two button states in Bit 3 and 4, in following order:
Bit4 4,3,C,8,u,u,u,u (0=Released, 1=Pressed) (u=Unused always 1) Bit3 2,1,5,9,6,A,B,7 (0=Released, 1=Pressed) |
Whereas, 1-C (hex) are button numbers 1-12 on Side B, or equivalent buttons on Side A (horizontally mirrored, of course).
| Controllers - Microphone |
Microphone
On older Famicoms, the second control pad (that without Start and Select
buttons) has a microphone with volume control built-in. The signal goes to
Bit 2 of Port 4016h (simple 1bit input, not an analogue ADC-converted input).
The signal is also merged with the PPUs sound output signals, as such,
allowing to use the television set/speaker as amplifier/megaphone.
| Controllers - Reset Button |
Reset Button
As an additional "control" the console is equipped with a reset button, which
is grounding the 2A03s /RST pin (resets CPU and APU).
On NES consoles (not on Famicom consoles), the reset signal is also connected
to PPU /SYNC input, causing the picture to be disabled during reset (the PPU
registers are left unchanged though). For curiosity, the NES reset signal is
also connected to the power LED, the LED goes off when pressing Reset (or
when the lockout chip generates a reset).
Anyways, RAM and VRAM is left unaffected, so that the program may recover
from reset by invoking a warmboot rather than complete coldboot. As simple
example, it may, if desired, preserve high score values, etc.
The cartridge bus doesn't include a reset signal, so mapper registers would
be usually left unaffected as well - unless any mappers figure out any
ridiculous ways to detect resets, for example by examing address signals.
The Reset button is also important for some games with battery backed SRAM:
The consoles cartridge bus becomes unstable during power-off, so that SRAM
content may get overwritten randomly. As workaround, some games prompt the
user to hold down the reset button during power-off (eg. Maniac Mansion,
MMC1). Other games include mappers that can enable/disable SRAM, and don't
need that trick (eg. Kirby's Adventure, MMC3).
| Controllers - Arcade Machines |
VS Unisystem
Arcade Machine with additional coin-detection and DIP-switch inputs.
Port 4016h/Write: Bit2 Select 8K VROM bank at PPU 0000h-1FFFh (Mapper 99 games only) Port 4016h/Read: Bit2 Credit Service Button (0=Released, 1=Service Credit) Bit3-4 DIP Switch 1-2 (0=Off, 1=On) Bit5-6 Credit Left/Right Coin Slot (0=None, 1=Coin) (Acknowledge via 4020h) Port 4017h/Read: Bit2-7 DIP Switch 3-8 (0=Off, 1=On) Port 4020h/Write: Bit0 Acknowlege Coin Slot Signal (0=Normal, 1=Acknowlege Coin) |
The controls are working like normal joypads, with different bits assignments, Start/Select are renamed to Button 1-4, and controls for Player 1 and 2 are exchanged:
Read NES/4016h VS/4016h NES/4017h VS/4017h 1st Button A (1) Button A (2) Button B (2) Button A (1) 2nd Button B (1) Button B (2) Button B (2) Button B (1) 3rd Select (1) Button 1 Select (2) Button 2 4th Start (1) Button 3 Start (2) Button 4 5th Up (1) Up (2) Up (2) Up (1) 6th Down (1) Down (2) Down (2) Down (1) 7th Left (1) Left (2) Left (2) Left (1) 8th Right (1) Right (2) Right (2) Right (1) |
Also note that the VS Unisystem uses different palettes than NES/Famicom.
Play Choice 10
Arcade Machine with additional coin-detection, DIP-switch, and game-select
inputs. The inputs are controlled by a separate Z80 CPU. More info:
Nintendo Playchoice 10
| Cartridges and Mappers |
General Cartridge Info
Cartridge Info
Mappers (Numbers as used in .NES fileformat)
Mapper 0: NROM - (No Mapper)
Mapper 1: MMC1 - PRG/32K/16K, VROM/8K/4K, NT
Mapper 2: UNROM - PRG/16K
Mapper 3: CNROM - VROM/8K
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
Mapper 5: MMC5 - BANKING, IRQ, SOUND, VIDEO, MULTIPLY, etc.
Mapper 6: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ
Mapper 7: AOROM - PRG/32K, Name Table Select
Mapper 8: FFE F3xxx - PRG/32K, VROM/8K, NT, IRQ
Mapper 9: MMC2 - PRG/24K/8K, VROM/4K, NT, LATCH
Mapper 10: MMC4 - PRG/16K, VROM/4K, NT, LATCH
Mapper 11: Color Dreams - PRG/32K, VROM/8K
Mapper 12: FFE F6xxx - Not specified, NT, IRQ
Mapper 13: CPROM - 16K VRAM
Mapper 15: X-in-1 - PRG/32K/16K, NT
Mapper 16: Bandai - PRG/16K, VROM/1K, IRQ, EPROM
Mapper 17: FFE F8xxx - PRG/8K, VROM/1K, NT, IRQ
Mapper 18: Jaleco SS8806 - PRG/8K, VROM/1K, NT, IRQ, EXT
Mapper 19: Namcot 106 - PRG/8K, VROM/1K/VRAM, IRQ, SOUND
Mapper 20: Disk System - PRG RAM, BIOS, DISK, IRQ, SOUND
Mapper 21: Konami VRC4A/VRC4C - PRG/8K, VROM/1K, NT, IRQ
Mapper 22: Konami VRC2A - PRG/8K, VROM/1K, NT
Mapper 23: Konami VRC2B/VRC4E - PRG/8K, VROM/1K, NT, (IRQ)
Mapper 24: Konami VRC6A - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
Mapper 25: Konami VRC4B/VRC4D - PRG/8K, VROM/1K, NT, IRQ
Mapper 26: Konami VRC6B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
Mapper 32: Irem G-101 - PRG/8K, VROM/1K, NT
Mapper 33: Taito TC0190/TC0350 - PRG/8K, VROM/1K/2K, NT, IRQ
Mapper 34: Nina-1 - PRG/32K, VROM/4K
Mapper 40: FDS-Port - Lost Levels
Mapper 41: Caltron 6-in-1
Mapper 42: FDS-Port - Mario Baby
Mapper 43: X-in-1
Mapper 44: 7-in-1 MMC3 Port A001h
Mapper 45: X-in-1 MMC3 Port 6000hx4
Mapper 46: 15-in-1 Color Dreams
Mapper 47: 2-in-1 MMC3 Port 6000h
Mapper 48: Taito TC190V
Mapper 49: 4-in-1 MMC3 Port 6xxxh
Mapper 50: FDS-Port - Alt. Levels
Mapper 51: 11-in-1
Mapper 52: 7-in-1 MMC3 Port 6800h with SRAM
Mapper 56: Pirate SMB3
Mapper 57: 6-in-1
Mapper 58: X-in-1
Mapper 61: 20-in-1
Mapper 62: X-in-1
Mapper 64: Tengen RAMBO-1 - PRG/8K, VROM/2K/1K, NT
Mapper 65: Irem H-3001 - PRG/8K, VROM/1K, NT, IRQ
Mapper 66: GNROM - PRG/32K, VROM/8K
Mapper 67: Sunsoft3 - PRG/16K, VROM/2K, IRQ
Mapper 68: Sunsoft4 - PRG/16K, VROM/2K, NT-VROM
Mapper 69: Sunsoft5 FME-7 - PRG/8K, VROM/1K, NT ctrl, SRAM, IRQ
Mapper 70: Bandai - PRG/16K, VROM/8K, NT
Mapper 71: Camerica - PRG/16K
Mapper 72: Jaleco Early Mapper 0 - PRG-LO, VROM/8K
Mapper 73: Konami VRC3 - PRG/16K, IRQ
Mapper 74: Whatever MMC3-style
Mapper 75: Jaleco SS8805/Konami VRC1 - PRG/8K, VROM/4K
Mapper 76: Namco 109 - PRG/8K, VROM/2K
Mapper 77: Irem - PRG/32K, VROM/2K, VRAM 6K+2K
Mapper 78: Irem 74HC161/32 - PRG/16K, VROM/8K
Mapper 79: AVE Nina-3 - VROM/8K
Mapper 80: Taito X-005 - PRG/8K, VROM/2K/1K, NT
Mapper 81: AVE Nina-6
Mapper 82: Taito X1-17 - PRG/8K, VROM/2K/1K
Mapper 83: Cony
Mapper 84: Whatever
Mapper 85: Konami VRC7A/B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
Mapper 86: Jaleco Early Mapper 2 - PRG/32K, VROM/8K
Mapper 87: Jaleco/Konami 16K VROM - VROM/8K
Mapper 88: Namco 118
Mapper 89: Sunsoft Early - PRG/16K, VROM/8K
Mapper 90: Pirate MMC5-style
Mapper 91: HK-SF3 - PRG/8K, VROM/2K, IRQ
Mapper 92: Jaleco Early Mapper 1 - PRG-HI, VROM/8K
Mapper 93: 74161/32 - PRG/16K
Mapper 94: 74161/32 - PRG/16K
Mapper 95: Namcot MMC3-Style
Mapper 96: 74161/32
Mapper 97: Irem - PRG HI
Mapper 99: VS Unisystem Port 4016h - VROM/8K
Mapper 100: Whatever
Mapper 105: X-in-1 MMC1
Mapper 112: Asder - PRG/8K, VROM/2K/1K
Mapper 113: Sachen/Hacker/Nina
Mapper 114: Super Games
Mapper 115: MMC3 Cart Saint
Mapper 116: Whatever
Mapper 117: Future
Mapper 118: MMC3 with different Name Tables
Mapper 119: MMC3 TQROM with VROM+VRAM Pattern Tables
Mapper 122: Whatever
Mapper 133: Sachen
Mapper 151: VS Unisystem - PRG/8K, VROM/4K
Mapper 152: Whatever
Mapper 160: Same as Mapper 90
Mapper 161: Same as Mapper 1
Mapper 180: Nihon Bussan - PRG HI
Mapper 182: Same as Mapper 114
Mapper 184: Sunsoft - VROM/4K
Mapper 185: VROM-disable
Mapper 187: No Info
Mapper 188: UNROM-reversed
Mapper 189: MMC3 Variant
Mapper 222: Dragon Ninja
Mapper 225: X-in-1
Mapper 226: X-in-1
Mapper 227: X-in-1
Mapper 228: X-in-1 Homebrewn
Mapper 229: 31-in-1
Mapper 230: X-in-1 plus Contra
Mapper 231: 20-in-1
Mapper 232: 4-in-1 Quattro Camerica
Mapper 233: X-in-1 plus Reset
Mapper 234: Maxi-15
Mapper 240: C&E/Supertone - PRG/32K, VROM/8K
Mapper 241: X-in-1 Education
Mapper 242: Waixing - PRG/32K, NT
Mapper 243: Sachen Poker - PRG/32K, VROM/8K
Mapper 244: C&E - PRG/32K, VROM/8K
Mapper 245: No Info (seems to be some sort of MMC3 variant)
Mapper 246: C&E - PRG/8K, VROM/2K, SRAM
Mapper 248: No Info
Mapper 249: No Info
Mapper 250: No Info
Mapper 251: No Info
Mapper 252: No Info
Mapper 254: No Info
Mapper 255: X-in-1 - (Same as Mapper 225)
| Cartridge Info |
General Info
Cartridge Overview
Cartridge ROM-Image File Formats
Cartridge IRQ Counters
Cartridge Bus Conflicts
Cartridge Cicurity Chip (CIC) (Lockout Chip)
Cartridge Game Genie
Cartridge Pin-Outs
| Cartridge Overview |
Standard Mappers
There are more than hundred different mappers, though most are unimportant,
the standard types are Mapper 0,1,2,3,4 for ROM-cartridges. And Mapper 20 for
Floppy disks.
Type Games Percent Mapper 0 (NROM) 446 12.5% Mapper 1 (MMC1) 723 20.3% Mapper 2 (UNROM) 397 11.2% Mapper 3 (CNROM) 273 7.7% Mapper 4 (MMC3) 784 22.1% Mapper 20 (FDS) ? x.x% Other Mappers 932 26.2% Total 3555 100.0% |
Other mapper types are used by less than 2% per type, though together they make up 26.2%.
Non-standard Mappers
Some mappers like MMC5 have been used only in a few newer cartridges. Several
third-party companies (Konami, Irem, Jaleco, Bandai, Sunsoft, etc.) have
developed their own mappers which are used only for their own games. That
mappers may be important to play specific games, though they are often used
only by 1-2 titles.
Also, there have been various pirate / multi-game cartridges manufactured,
containing modified ROM-images with custom mapper circuits, these mappers are
completely unimportant since the original games used standard mappers.
Maximum manufactured ROM Size
The largest single NES game that I know of is Dragonquest 4 / Dragon Warrior
4. It has 1 megabyte of program ROM. Also, the Japanese game Metal Slader
Glory has 512K of PRG and 512K of CHR ROM, making it also a full megabyte.
Several pirate/unlicenced Famicom games are also pretty large.
Minimum manufactured ROM Size
Although the .NES fileformat deems 16K PRG ROM games as the minimum, there
have been some 8K games manufactured, such as Galaxian. Later on, skilled
programmers have learned to squeeze better code into even less memory, but
nowadays most are probably dead.
Banking Granularity
PRG ROM is usually split into banks of 8K, 16K, or 32K, a few mappers like
MMC5 also have smaller 1K SRAM banks. VROM is usually split into banks of 1K,
2K, 4K, or 8K.
Note on Mapper Descriptions
In this document Bank Selections are sometimes described as 4K, or as 4x1K.
The linear address for a 4K bank is (N*4096).
The linear address for a 4x1K bank is ((N AND (NOT 3))*1024).
Ie. in the latter case, the bank value is specified in 1K-steps, with lower
bits ignored, and rounded down to a 4K boundary.
Mapper Reset
In general, mapper registers are uninitialized on reset/power-up, and should
be initialized by software; if memory at FFFCh is mappable, then valid reset
vectors (and reset handlers) should be contained in all banks.
There is no reset signal available on cartridge bus, possible ways to detect
reset are to sense inactivity on A0 or PHI2 lines, to sense reads from the
reset vector at FFFCh, or to use power-up capacitors for coldboot detection
(though that not for warmboot).
Caution: Several mappers in this document are described to have initial
settings on reset or power-up. Most of that info has been taken from other
documents, in most cases that is unconfirmed, and probably incorrect. A few
mappers seem to be actually containing reset circuits though.
| Cartridge ROM-Image File Formats |
iNES Format (.NES)
This fileformat and mapper-numbers have been designed/assigned by Marat
Fayzullin (author of iNES emulator), please contact him if you want to make
any changes to the format or numbers. The file header is 16 bytes:
00h File ID ('NES',1Ah)
04h Number of 16K PRG-ROM pages
05h Number of 8K CHR-ROM pages (00h=None / VRAM)
06h Cartridge Type LSB
Bit7-4 Mapper Number (lower 4bits)
Bit3 1=Four-screen VRAM layout
Bit2 1=512-byte trainer/patch at 7000h-71FFh
Bit1 1=Battery-backed SRAM at 6000h-7FFFh, set only if battery-backed
Bit0 0=Horizontal mirroring, 1=Vertical mirroring
07h Cartridge Type MSB (ignore this and further bytes if Byte 0Fh nonzero)
Bit7-4 Mapper Number (upper 4bits)
Bit3-2 Reserved (zero)
Bit1 1=PC10 game (arcade machine with additional 8K Z80-ROM) (*)
Bit0 1=VS Unisystem game (arcade machine with different palette)
08h Number of 8K RAM (SRAM?) pages (usually 00h=None-or-not-specified)
09h Reserved (zero)
0Ah Reserved (zero) (sometimes 03h,10h,13h,30h,33h purpose unknown) (*)
0Bh Reserved (zero)
0Ch Reserved (zero)
0Dh Reserved (zero)
0Eh Reserved (zero)
0Fh Nonzero if [07h..0Fh]=GARBAGE, if so, assume [07h..0Fh]=ALL ZERO (*)
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Followed by 512 byte trainer (if any, see Byte 6, Bit 2, mainly FFE games).
Followed by N*16K PRG-ROM pages (see Byte 4).
Followed by N*8K CHR-ROM pages (if any, see Byte 5).
Followed by 8K Play Choice 10 Z80-ROM (if any, see Byte 7, Bit 1) (*).
Followed by 128 (or 127) bytes title at end of file (ASCII, zero-padded) (*).
Items marked as (*) are regulary used, but not offical part of the format.
Many PC10 files declare Z80-ROM as additional VROM bank (instead Byte7/Bit1).
.UNF - Universal NES Image File Format (UNIF) by Tennessee Carmel-Veilleux
A "newer" fileformat dated back to 2000, the relation between iNES mapper
numbers and UNIF MAPR names is still undocumented, and of course nobody uses
files with .UNF extension. Still, it's having one or two useful features, and
may become more popular if somebody dares to fix the MAPR problem, and to
rename it from .UNF to .NES extension.
File Header (32 bytes)
00h-03h: "UNIF" tag identifier
04h-07h: Revision number ("currently 4, for REV 7b, Revision 6 of UNIF" Huh!)
08h-1Fh: Reserved for future usage
|
The header is followed by whatever chunks, all chunks are optional, and may or may not be included in the file, only the PRG0 one is obviously required. Software may skip any chunks which are uninteresting or unrecognized, each chunk formatted as such:
00h-03h: Chunk ID string (4-letter ASCII, described below) 04h-07h: Length of Data Block in bytes (excluding above ID and length entry) 08h... : Data |
MAPR - Board Name (aka Mapper) (ASCIZ, suggested max: 32 chars)
This uses ASCIZ strings to describe the board names (instead of iNES mapper numbers), it's meant to be more specific than mapper numbers, for example, it's using different names for different MMC1-boards. http://www.parodius.com/~veilleux/boardtable.txt http://www.parodius.com/~veilleux/boardnames |
PRG0..PRGF - Binary data of the PRG ROM
CHR0..CHRF - Binary data of the CHR ROM (aka VROM in general)
Normally using only PRG0 (and CHR0, if VROM used). In rare cases, if the cart contains more than 1 PRG (or CHR) ROM chip, then PRG1-F and CHR1-F may be used for the additional chips. |
TVCI - Television Standards Compatability Information (One Byte)
00h 60Hz/NTSC (USA, Japan, etc.) 01h 50Hz/PAL (Germany, etc.) 02h Compatible with both 50Hz and 60Hz refresh rates |
CTRL - Controllers used by the cartridge (currently only 1 Byte / 8bit)
Bit0 Regular Joypad Bit1 Zapper Bit2 R.O.B Bit3 Arkanoid Controller (presumably Paddle) Bit4 Power Pad Bit5 Four-Score adapter (NES 4-player adapter) (Not Famicom adapter!) Bit6-7 Reserved |
MIRR - Name Table Mirroring (1 Byte)
00h Two-Screen Horizontal Mirroring (Hard Wired) 01h Two-Screen Vertical Mirroring (Hard Wired) 02h Single-Screen BLK0 (Hard Wired) 03h Single-Screen BLK1 (Hard Wired) 04h Four-Screens of VRAM (Hard Wired) 05h Mirroring Controlled By Mapper Hardware |
BATR - Battery installed on Board (1 dummy byte)
Presence of this chunk means yes, absence means no. |
NAME - Game Title, ASCIZ String
Game Title |
READ - Readme/Comments/Notes/Credits
Probably some sort of ASCII text of unspecified formatting |
VROR - Allow homebrewn games to over-write VROM (1 dummy byte)
Presence of this chunk means yes, absence means no. |
PCK0..PCKF - 32-bit CRCs for PRG0..PRGF blocks (4 bytes, each)
CCK0..CCKF - 32-bit CRCs for CHR0..CHRF blocks (4 bytes, each)
Intended "to make sth sure on EPROMs" ;-) Checksum algorythm not specified. |
DINF - Dumper information block (204 Bytes)
100 bytes ASCIZ name of the person who dumped the cart 4 bytes day, month, year-lsb, year-msb when cartridge was dumped 100 bytes ASCIZ agent "name of the ROM-dumping means used" |
Note: All words and dwords in header/chunks stored LSB first.
| Cartridge IRQ Counters |
The MMC3's scanline counter
The MMC3 bases it's scanline counter on PPU address line A13 (which is why
IRQ's can be fired off manually by toggling A13 a bunch of times via $2006).
A13 cycles (0 -> 1) exactly 42 times per scanline, whereas the CPU count of
cycles per scanline is not an exact integer (113.67).
Konami IRQ counters
Running at 113.75 cycles, including during VBlank.
Famicom Disk System IRQ counters
Allows to count clock cycles, rather than scanlines.
| Cartridge Bus Conflicts |
/PRG Pin - Indicates CPU Memory Access to 8000h-FFFFh (LOW=Read or Write)
R/W Pin - Indicates CPU Direction (LOW=Write, HIGH=Read)
The /PRG Pin indicates read-or-write access to the PRG ROM memory area at
8000h-FFFFh, the read/write direction could be determined by R/W Pin. Most
cartridges are ignoring the R/W signal, and are assuming all memory accesses
to be read-requests (which makes sense since ROM is read-only).
However, many cartridges have write-only mapper ports at 8000h-FFFFh,
activated when /PRG=LOW and R/W=LOW. Many of these carts (especially simple
TTL circuits like UNROM, CNROM, etc.) still activate ROM on any /PRG signal
without checking R/W, so that ROM outputs data simultaneously with the CPU
writing data to the mapper port.
Common workaround is to write to a ROM address that contains a value equal to
the written value. Also one could probably write to an address that contains
FFh (low signals are stronger than high signals, so the values would be
logically, or 'forcefully' ANDed. Don't know about any games using that
method though). Another workaround is to interprete the lower address bits
instead of the data bits (eg. Mapper 225), that's of course still producing a
bus-conflict (shortcut), but without disturbing the program flow.
| Cartridge Cicurity Chip (CIC) (Lockout Chip) |
Lockout chips are contained in most NES consoles, and in all NES cartridges.
Both chips are generating an identical serial data stream, and, everything
works fine if the streams match. Otherwise the chip in the console issues a
1Hz reset signal - the cartridge will be permanently restarted, screen will
be flashing, and the power LED blinks.
That mechanism is intended both to prevent software piracy, and to prevent
third party developers from distrubting (unlicensed) games. Also, an US
cartridge won't work on a UK console and vice versa, because of different
lockout chip versions used in different countries:
3193A NES, USA 3195A NES, European 3196A NES, Hong Kong 3197A NES, UK N/A NES, newer top-loading version (1993-1995) N/A Famicom, Japan (1983-1995) |
The chips have been invented when releasing the NES in 1985, the original Famicom didn't have lockout chips, nor do newer Famicoms, for backwards compatibility reasons. There have been also some lockout chip revisions to make newer NES consoles incompatible with some "faked" lockout chips from other manufacturers.
The lockout chips are 4bit microprocessors in DIL16 package with a built-in
program called 10NES, and are connected to S0,S1,S2,4MHz pins of the 72pin
NES cartridge slot. Pin 4 of the chip is used to configure the chip:
HIGH (+5V) Lock, used in console LOW (GND) Key, used in cartridge |
To disable the chip in the console, wire that pin to GND instead of 5V, the NES will then work with any cartridges with or without lockout chip, and with cartridges from other countries - though some NTSC (60Hz) games may be incompatible with PAL (50Hz) refresh rates, and vice versa.
| Cartridge Game Genie |
The Game Genie is an adapter to be connected between the console and game
cartridge, it includes a BIOS ROM which prompts the user to enter 6-letter or
8-letter cheat-codes, and then starts the actual game.
The adapter compares the CPU address bus (PRG ROM area 8000h-FFFFh), and
optionally also the CPU data bus (reduces the risk to mess-up values in other
banks in cartridges with Memory Mappers), if the comparision matches, then
the value on data bus will be replaced.
Code Format
The letters are translated into 4bit Hex-digits:
Hex 0 1 2 3 4 5 6 7 8 9 A B C D E F Letter A P Z L G I T Y E O X U K S V N |
Address/Data/Compare bits A14-A0, D7-D0, C7-C0 are scrambled as such:
Char Bit3 Bit2 Bit1 Bit0 Char Bit3 Bit2 Bit1 Bit0 1st D7 D2 D1 D0 2nd A7 D6 D5 D4 3rd LEN A6 A5 A4 4th A3 A14 A13 A12 5th A11 A2 A1 A0 6th CD3 A10 A9 A8 7th C7 C2 C1 C0 8th D3 C6 C5 C4 |
6-Letter code: LEN=0, CD3 used as D3, acts as "[A]=D"
8-letter code: LEN=1, CD3 used as C3, acts as "If [A]=C then [A]=D"
Example: Code "SXIOPO" changes [91D9h]=ADh (Infinite lives in smb1).
| Cartridge Pin-Outs |
60-Pin Famicom Cartridge connector
1 GND 19-25 PPU A6-A0 45 EXP SND_IN 2-13 CPU A11-A0 26-29 PPU D0-D3 45,46 EXP SND_OUT 14 CPU R/W 30-31 +5VDC 47 PPU /WR 15 CPU /IRQ 32 PHI2 CLK 48 PPU NT /CS 16 GND 33,35 CPU A12-A14 49 PPU NT /A13 17 PPU /RD 36-43 CPU D7-D0 49-56 PPU A7-A12,A13 18 PPU NT A10 44 CPU /PRG 57-60 PPU D7-D4 |
72-Pin NES Cart connector
Pin Dir Use Expl. 1 Out VEE GND 2-13 Out CPU A11-A0 14 Out CPU R/W 15 I/O CPU /IRQ 16-20 I/O EXP Expansion Port Pins 42-38 (not used by the console itself) 21 Out PPU /R 22 In PPU VA10 (A10 of internal 2K VRAM, ie. select BLK0 or BLK1) 23-29 Out PPU A6-A0 30-33 I/O PPU D0-D3 34-35 I/O CIC S0-S1 (cicurity/lockup chip protocol signals) 36 Out VCC +5VDC 37 Out CPU 21.47727MHz (NTSC), 26.601712MHz (PAL) 38 Out CPU PHI2 39-41 Out CPU A12-A14 42-49 I/O CPU D7-D0 50 Out CPU /PRG (PRG-ROM access, logical NAND of PHI2 and CPU A15) 51-55 I/O EXP Pins 06-10 56 Out PPU /W 57 In PPU /VCS (internal 2K VRAM Chip-Select) 58 Out PPU /A13 (inverted A13, wired to /VCS when used as name table) 59-65 Out PPU A7-A9,A11,A10,A12-A13 66-69 I/O PPU D7-D4 70 I/O CIC S2 (cicurity/lockup chip protocol signals) 71 Out CIC 4Mhz (cicurity/lockout chip clock line) 72 Out VEE GND |
| Mapper 0: NROM - (No Mapper) |
No mapper used in games with 32K ROM + 8K VROM (or less).
Name Table can be hardwired either to Horizontal or Vertical Mirroring.
| Mapper 1: MMC1 - PRG/32K/16K, VROM/8K/4K, NT |
This mapper is used on numerous U.S. and Japanese games, including Legend of
Zelda, Metroid, Rad Racer, Mega Man 2, and many others.
8000h-FFFFh
Bit 0 Serial data loaded to 5bit shift register (LSB=1st write)
Bit 7 Clear 5bit shift register (1=Reset, next write will be "1st write")
|
On fifth write, data in shift register is copied to Register 0..3 (depending on upper address bits), and the shift register is automatically cleared.
8000h-9FFFh Register 0 - Configuration Register
Bit0-1 Name Table Mirroring
0,1 Single-Screen (BLK0 only)
2 Two-Screen Vertical Mirroring
3 Two-Screen Horizontal Mirroring
Bit2-3 PRG-Switching Mode (usually 3)
0,1 Switchable 32K Area at 8000h-FFFFh (via Register 3)
2 Switchable 16K Area at C000h-FFFFh (via Register 3)
And Fixed 16K Area at 8000h-BFFFh (always 1st 16K)
3 Switchable 16K Area at 8000h-BFFFh (via Register 3)
And Fixed 16K Area at C000h-FFFFh (always last 16K)
Bit4 VROM Switching Size (for carts with VROM)
0 Swap 8K of VROM at PPU 0000h
1 Swap 4K of VROM at PPU 0000h and 1000h
A000h-BFFFh Register 1
Bit4-0 Select 4K or 8K VROM bank at 0000h (4K and 8K Mode, see Reg0/Bit4)
C000h-DFFFh Register 2
Bit4-0 Select 4K VROM bank at 1000h (used in 4K Mode only, see Reg0/Bit4)
E000h-FFFFh Register 3
Bit3-0 Select 16K or 2x16K ROM bank (see Reg0/Bit3-2)
Bit4 Unused ?
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Initially 1st and last 16K are mapped to 8000h and C000h.
In 32K PRG and 8K VROM mode, bank numbers specified in steps of two.
Register 3 is restricted to sixteen 16K banks, cartridges with more than 256K
PRG ROM use Bit4 of Register 0-2 to expand the available memory area:
Register 0, Bit 4 <1024K carts> 0 = Ignore 256K selection register 1 1 = Acknowledge 256K selection register 1 Register 1, Bit4 - 256K ROM Selection Register 0 <512K carts> 0 = Swap banks from first 256K of PRG 1 = Swap banks from second 256K of PRG <1024K carts with bit 4 of register 0 off> 0 = Swap banks from first 256K of PRG 1 = Swap banks from third 256K of PRG <1024K carts with bit 4 of register 0 on> Low bit of 256K PRG bank selection Register 2, Bit4 - 256K ROM Selection Register 1 <1024K carts with bit 4 of register 0 off> Store but ignore this bit (base 256K selection on 256K selection Reg 0) <1024K carts with bit 4 of register 0 on> High bit of 256K PRG bank selection |
Reportedly some MMC1 carts have 16K SRAM, of which only 8K are battery
backed, no idea how/where the additionally 8K are accessed, and no idea which
8K are battery backed and which are not (?).
| Mapper 2: UNROM - PRG/16K |
This mapper is used on many older U.S. and Japanese games, such as
Castlevania, Mega Man, Ghosts & Goblins, and Amagon.
8000h-FFFFh Select 16K ROM bank at 8000h-BFFFh (initially 1st bank) N/A Fixed 16K ROM at C000h-FFFFh (always last bank) |
All carts using it have 8K of VRAM at PPU 0000h. Most carts with this mapper are 128K. A few, mostly Japanese carts, such as Final Fantasy 2 and Dragon Quest 3, are 256K.
Bus-conflicts. Uses a 74LS161 chip (connection: /PRG-CLK, R/W-/LOAD), and its
outputs are each ORed with A14 by a 74LS32 chip.
Board NES-UN-ROM-05 and Konami 531320 (both using only 3bits / 8banks)
| Mapper 3: CNROM - VROM/8K |
This mapper is used on many older U.S. and Japanese games, such as Solomon's
Key, Gradius, Cybernoid, and Hudson's Adventure Island.
8000h-FFFFh Bit 0-1 Select 8K VROM bank at PPU 0000h (initially 1st bank) Bit 4-5 Name Table Mirroring Select? |
Bus-conflicts. Uses a 74LS161 chip (connection: /PRG-CLK, R/W-/LOAD), circuit for name table outputs is unknown?
Cybernoid supports both above Port 8000h-FFFFh, and alternately Port 6000h.
| Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ |
A great majority of newer NES games (early 90's) use this mapper, both U.S.
and Japanese. Among the better-known MMC3 titles are Super Mario Bros. 2 and
3, Mega Man 3, 4, 5, and 6, and Crystalis.
8000h Index/Control (5bit)
Bit7 CHR Address Select (0=Normal, 1=Address Areas XOR 1000h)
Bit6 PRG Register 6 Area (0=8000h-9FFFh, 1=C000h-DFFFh)
Bit2-0 Command Number
0 - Select 2x1K VROM at PPU 0000h-07FFh (or 1000h-17FFh, if Bit7=1)
1 - Select 2x1K VROM at PPU 0800h-0FFFh (or 1800h-1FFFh, if Bit7=1)
2 - Select 1K VROM at PPU 1000h-13FFh (or 0000h-03FFh, if Bit7=1)
3 - Select 1K VROM at PPU 1400h-17FFh (or 0400h-07FFh, if Bit7=1)
4 - Select 1K VROM at PPU 1800h-1BFFh (or 0800h-0BFFh, if Bit7=1)
5 - Select 1K VROM at PPU 1C00h-1FFFh (or 0C00h-0FFFh, if Bit7=1)
6 - Select 8K ROM at 8000h-9FFFh (or C000h-DFFFh, if Bit6=1)
7 - Select 8K ROM at A000h-BFFFh
N/A - Fixed 8K ROM at C000h-DFFFh (or 8000h-9FFFh, if Bit6=1)
N/A - Fixed 8K ROM at E000h-FFFFh (always last 8K bank)
8001h Data Register (Indexed via Port 8000h)
A000h Mirroring Select (Bit0: 0=Vertical, 1=Horizontal Mirroring)
A001h SaveRAM Toggle (Bit7: 0=Disable 6000h-7FFFh, 1=Enable 6000h-7FFFh)
C000h IRQ Counter Register - The IRQ countdown value is stored here.
C001h IRQ Latch Register - A temporary value is stored here.
E000h IRQ Control Register 0
Any value written here will disable IRQ's and copy the
latch register to the actual IRQ counter register.
E001h IRQ Control Register 1 - Any value written here will enable IRQ's.
|
The fixed PRG banks are always the LAST two 8K banks in the cart.
On carts with VROM, the first 8K of VROM is swapped into PPU $0000 on reset.
On carts without VROM, as always, there is 8K of VRAM at PPU $0000.
The IRQ counter is decremented each scanline, based on PPU address line A13
which toggles between Pattern Tables (LOW) and Name Tables (HIGH) 42 times
per scanline. The counter is paused during VBlank, which allows to use the
same settings for PAL and NTSC timings. Note that the counter gets clocked,
even during VBlank, when toggling A13 a bunch of times via Port 2006h.
Multicarts with MMC3 and additional Game-Select Ports
Mapper 44: 7-in-1 MMC3 Port A001h
Mapper 45: X-in-1 MMC3 Port 6000hx4
Mapper 47: 2-in-1 MMC3 Port 6000h
Mapper 49: 4-in-1 MMC3 Port 6xxxh
Mapper 52: 7-in-1 MMC3 Port 6800h with SRAM
| Mapper 5: MMC5 - BANKING, IRQ, SOUND, VIDEO, MULTIPLY, etc. |
Used by Gun Sight (Laser Invasion), Uchuu Keibitai SDF, Bandit Kings
(Suikoden), Castlevania 3, Nobunaga Sengoku (Nobunaga's Ambition 2), Nobunaga
Bushou, Shin 4 Nin Uchi Mahjong, Ishin no Arashi, L'Empereur, Ganbare Goemon
Gaiden (bugged hack?), Romance of the Three Kingdoms 2 (Sangokushi 2),
Gemfire (Royal Blood), Uncharted Waters (Daikoukai Jidai), Aoki Ookami, Just
Breed, Metal Slader Glory.
Mapper 5: MMC5 - I/O Map
Mapper 5: MMC5 - CPU Memory Control
Mapper 5: MMC5 - Video Name Table
Mapper 5: MMC5 - Video Pattern Table
Mapper 5: MMC5 - Video Split and IRQ
Mapper 5: MMC5 - Video EXRAM
Mapper 5: MMC5 - Sound Control
Mapper 5: MMC5 - Other Registers
| Mapper 5: MMC5 - I/O Map |
Summary of all MMC5 Registers
5000h Sound Channel 1 Pulse Control 5002h Sound Channel 1 Frequency LSB 5003h Sound Channel 1 Frequency MSB 5004h Sound Channel 2 Pulse Control 5006h Sound Channel 2 Frequency LSB 5007h Sound Channel 2 Frequency MSB 5010h Sound Channel 3 Enable 5011h Sound Channel 4 Synthetic Voice business channel 2 5015h Sound Channel 1 and 2 Enable 5100h PRG Bank Size (Mode for Port 5114h-5117h) 5101h CHR Bank Size 5102h RAM Write Protect Key 1 5103h RAM Write Protect Key 2 5104h EXRAM Mode Setting 5105h Name Table Select 5106h Name Table Fill-Mode Tile Number 5107h Name Table Fill-Mode Palette Number 5113h-5117h PRG Bank Selection Registers 5120h-5127h CHR Bank Selection for Sprites and for CPU Access 5128h-512Bh CHR Bank Selection for Background 5130h Unknown 5200h Horizontal Split Control 5201h Horizontal Split Scroll Position 5202h Horizontal Split CHR Bank Selection 5203h Vertical IRQ Counter 5204h Vertical IRQ Control/Status (R/W) 5205h Multiply unit input/output 5206h Multiply unit input/output 5800h Unknown 5C00h-5FFFh EXRAM (1K) |
Ports 5102h-5103h, 5105h-5107h, 5200h-5203h are Write Only.
Ports 5204h-5206h are Read/Write. Other Ports unknown.
| Mapper 5: MMC5 - CPU Memory Control |
5100h - PRG Bank Size Control (Mode for Port 5114h-5117h)
Bit7-2 Not used Bit1-0 PRG Bank Size (0=32K, 1=16K, 2=Mixed, 3=8K) |
5102h-5103h - RAM Write Protect Keys
5102h RAM Write Protect Key 0 (Lower 2bit must be 02h for write-enable) 5103h RAM Write Protect Key 1 (Lower 2bit must be 01h for write-enable) |
RAM is always read-able, but is write-able only with above settings.
5113h-5117h - PRG Bank Selection Registers
Port Type Mode3/8K Mode2/Mixed Mode1/16K Mode0/32K 5113h RAM 8K at 6000h 8K at 6000h 8K at 6000h 8K at 6000h 5114h ROM/RAM 8K at 8000h, N/A , N/A , N/A 5115h ROM/RAM 8K at A000h, 2x8K at 8000h, 2x8K at 8000h, N/A 5116h ROM/RAM 8K at C000h, 8K at C000h, N/A , N/A 5117h ROM 8K at E000h, 8K at E000h, 2x8K at C000h, 4x8K at 8000h |
Lower one or two bits of 2x8K or 4x8K bank numbers are ignored.
RAM bank selection via Port 5113h-5116h (not 5117h):
Bit7 ROM/RAM Mode (0=RAM, 1=ROM) (Port 5114h-5116h only, not 5113h,5117h) Bit6-3 Not used Bit2 RAM Chip Select (0=1st chip, 1=2nd chip, or open bus if single chip) Bit1-0 Select 8K RAM Bank in currently selected RAM chip (32K chips only) |
Existing RAM configurations are: 8K (single 8K chip), 16K (two 8K chips),
and 32K (single 32K chip).
On reset, 8K mode is activated, and all ROM banks are set to the LAST 8K bank
in the cartridge.
| Mapper 5: MMC5 - Video Name Table |
5105h - Name Table Select
Bit1-0 Select NT0 VRAM at 2000h-23FFh (0=BLK0, 1=BLK1, 2=EXRAM, 3=FILLMODE) Bit3-2 Select NT1 VRAM at 2400h-27FFh (0=BLK0, 1=BLK1, 2=EXRAM, 3=FILLMODE) Bit5-4 Select NT2 VRAM at 2800h-2BFFh (0=BLK0, 1=BLK1, 2=EXRAM, 3=FILLMODE) Bit7-6 Select NT3 VRAM at 2C00h-2FFFh (0=BLK0, 1=BLK1, 2=EXRAM, 3=FILLMODE) |
If it isn't used for other purpose, then EXRAM can be used as 3rd Name-table.
5106h - Name Table Fill-Mode Tile Number (Bit7-0)
5107h - Name Table Fill-Mode Palette Number (only Bit1-0 used)
In FILLMODE, the entire Name-table is filled by Port 5106h/5107h settings.
| Mapper 5: MMC5 - Video Pattern Table |
5101h - CHR Page Size
Bit7-6 Not used Bit1-0 CHR Bank Size (0=8K, 1=4K, 2=2K, 3=1K) |
Bank selection registers below are 8bit, so 1K mode can address only 256K VROM, 8K mode could address up to 2MB VROM.
5120h-5127h - CHR Bank Selection for Sprites and for CPU Access
Port Mode3/1K Mode2/2K Mode1/4K Mode1/8K 5120h 1K at 0000h N/A N/A N/A 5121h 1K at 0400h 2K at 0000h N/A N/A 5122h 1K at 0800h N/A N/A N/A 5123h 1K at 0C00h 2K at 0800h 4K at 0000h N/A 5124h 1K at 1000h N/A N/A N/A 5125h 1K at 1400h 2K at 1000h N/A N/A 5126h 1K at 1800h N/A N/A N/A 5127h 1K at 1C00h 2K at 1800h 4K at 1000h 8K at 0000h |
Used for Sprite Tiles (not for Background Tiles), and also used for CPU VRAM Access via Port 2006h/2007h.
5128h-512Bh - CHR Bank Selection for Background
5128h 1K at X000h N/A N/A N/A 5129h 1K at X400h 2K at X000h N/A N/A 512Ah 1K at X800h N/A N/A N/A 512Bh 1K at XC00h 2K at X800h 4K at X000h 8K at 0000h |
Used for Background Tiles, the "XN00h" addresses in 1K,2K,4K are shared for both Pattern Tables at 0N00h and 1N00h, ie. BG Pattern Table selection in Port 2000h/Bit4 doesn't matter (except in 8K mode).
Other Background CHR Bank Selection Modes (which do not use 5128h-512Bh)
In Horizontal Split Mode, left or right BG Tiles use 4K CHR bank in Port 5202h.
In ExGrafix Mode, 4K CHR banks are specified for each single BG Tile in EXRAM.
| Mapper 5: MMC5 - Video Split and IRQ |
MMC5 allows to split the screen horizontally and vertically.
Horizontal Split is handled by hardware (automatically mid-scanline).
Vertical Split is to be handled by software (upon IRQ during HBlank).
5200h - Horizontal Split Control
Bit7 For the E function (0=Don't use, 1=Use)
Bit6 Boundary's side is for using Split Mode extension of graphics
(0=Left side, 1=Right side)
Bit5 Not used
Bit4-0 Left boundary is designated with the char. # to count places
|
Used by Uchuu Keibitai SDF, most or all other games don't use H-Split.
Examples for 5200h Settings: 00h (not?) used yet 82h Used for SplitMode GFX extension from left 1-2 character C2h Used for SplitMode GFX extension from the right side 3 chars. C0h Used for SplitMode GFX extension on the whole screen D0h Used for SplitMode GFX extension on the right side of the screen 90h Used for SplitMode GFX extension on the left side of the screen |
5201h - Horizontal Split Scroll Position
"$2005 determines the vertical movement; it can also delay ext. gfx's vert.
movement if necessary. It's written 2 times in bulk in the same way as it
would slip off a grade in $2005."
5202h - Horizontal Split CHR Bank Selection
Bit7-6 Not used Bit5-0 Select 4K VROM at both 0000h-0FFFh and 1000h-1FFFh |
Presumably used for BG Tiles in the Horizontal Split area, instead of the normal BG-CHR Bank Selection via 5128h-512Bh.
5203h - Vertical IRQ Counter
MMC3-style, decremented each scanline, paused during VBlank.
A setting of 00h seems to disable the counter (or, maybe sets it to 256 lines).
5204h - Vertical IRQ Control/Status (R/W)
Bit7/Write IRQ Enable (0=Disable, 1=Enable) Bit6/Read Unknown |
Reading from 5204h automatically acknowledges IRQs, and probably also returns the current status of the IRQ flag in one bit.
Bit6 contains whatever flag, it seems to be NOT directly IRQ related - many
games do never write to 5203h/5204h, but still expect Bit6 to toggle on/off.
| Mapper 5: MMC5 - Video EXRAM |
5C00h-5FFFh - EXRAM
Built-in 1K RAM, can be used in different modes, as VRAM or as WRAM.
5104h - EXRAM Mode Setting
Bit7-6 Not used
Bit1-0 Select EXRAM Mode
0 VRAM Extra Name Table (via Port 5105h)
1 VRAM ExGrafix Color Expansion (see below)
2 General purpose WRAM (read/write)
3 General purpose WRAM (write protected)
|
In VRAM modes, EXRAM can be probably accessed during VBlank only (just as normal VRAM). In WRAM modes, EXRAM can be probably accessed at any time, for use as general purpose Work RAM, instead of (or additionally to) normal SRAM.
ExGrafix Mode (used by most MMC5 titles, except Castlevania 3)
5C00h-5FBFh - Tile Number banks and Palettes for 32x30 Tiles
Bit7-6 Palette Number for each Tile Bit5-0 4K Bank Number for each Tile |
The 6bit Bank Numbers expand each of the 8bit Tile Numbers in Name Table entries 000h-3BFh to 14bit Tile Numbers (max 256K VROM addressable). The Palette Numbers allow to specify different palettes for each single Tile, instead of the normal Name Table palettes which share one palette entry for each 4 Tiles.
Name Table entries 3C0h-3FFh and EXRAM 5FC0h-5FFFh are not used in this mode.
Also BG-CHR Bank Selection Ports 5128h-512Bh are not used.
| Mapper 5: MMC5 - Sound Control |
MMC5 Sound, Japanese 60pin Famicom carts only, not NES 72pin carts.
5000h Sound Channel 1 Pulse Control
5004h Sound Channel 2 Pulse Control
Bit7-6 Duty Cycle (0..3 = 87.5%, 75.0%, 50.0%, 25.0%) Bit5 Waveform Hold (e.g. Looping) (0=Off, 1=On) Bit4 Envelope Select (0=Varied, 1=Fixed) Bit3-0 When Bit4=0: Playback Rate (0..0Fh = Fast..Slow) Bit3-0 When Bit4=1: Output Volume (0..0Fh) |
5002h Sound Channel 1 Frequency LSB
5006h Sound Channel 2 Frequency LSB
Bit7-0 Lower 8bit of 11bit Frequency |
5003h Sound Channel 1 Frequency MSB
5007h Sound Channel 2 Frequency MSB
Bit7-3 Sound Occurence Time Bit2-0 Upper 3bit of 11bit Frequency |
5010h Sound Channel 3 Enable
Bit7-1 Not used Bit0 Wave output (0=Off, 1=On) |
5011h ch4 Synthetic Voice business channel 2
Bit7-0 Wave Size |
5015h Sound Channel 1 and 2 Enable
Bit7-2 Not used Bit1 Channel 2 (0=Disable, 1=Enable) Bit0 Channel 1 (0=Disable, 1=Enable) |
| Mapper 5: MMC5 - Other Registers |
5205h - WR multiply unit input/output
5206h - WR multiply unit input/output
($5205in)*($5206in) = $5205,$5206out
Result seems to be 16bit, 5205h=LSB, 5206h=MSB (?)
5130h - Unknown
Just Breed, Gun Sight, and Uchuu Keibitai SDF write 00h to this address.
5800h - Unknown
Just Breed writes 0xh to this address.
| Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches |
Front Far East (FFE) disk drive "backup unit" connects to the cartridge slot,
allows to load copies of games from floppy/hdd/cdrom into RAM (max 512K) and
VRAM (max 256K).
FFE Mapper Modes
Mapper 2: UNROM - PRG/16K
Mapper 6: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ
Mapper ?: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ
Mapper 8: FFE F3xxx - PRG/32K, VROM/8K, NT, IRQ
Mapper 12: FFE F6xxx - Not specified, NT, IRQ
Mapper 17: FFE F8xxx - PRG/8K, VROM/1K, NT, IRQ
FFE IRQ Registers
4501h IRQ Disable/Acknowledge (write any value, usually 00h) 4502h IRQ set lower 8bit of 16bit counter 4503h IRQ set upper 8bit of 16bit counter and Start/Enable IRQs |
IRQ counter is incremented each clock cycle, and produces IRQ on overflow.
FFE Trainers/Patches
All FFE games are patched to work with the "FFE" mappers. In case that the
patches don't fit into normal ROM area, additional 512-byte patches are often
located in SRAM area at 7000h-71FFh (or, in a few cases, reportedly at
5D00h), that patch-area may be used to handle FFE memory mapping, or for
cheats/trainers. Some MMC games also contain similar trainers (maybe working
on FFE device, if it supports MMC mappers?, or otherwise working on emulators
only).
FFE Configuration Registers
Configuration Registers are initialized before the game is started, so most
games don't need to access these registers, except for changing Name Table /
Mirroring bits. A few games might also change the mode bits.
42FCh-42FFh Configuration Register 1
A0 Name Table Mode (0=One-Screen, 1=Two-Screen) (with D4 below)
A1 Unknown (0=WE, 1=SW) (usually 1)
D7-D5 Memory Mode (0-7) "*MODE"
1 Mapper 6 F4xxx
2 Mapper 2 UNROM
3 Mapper ? F4xxx
4 Mapper 8 F3xxx/GNROM
0,5-7 unknown (Great Tank uses settings 1 and 6)
? unknown how to select Mapper 12 and Mapper 17
|
0 Mapper 17 (Kaiketsu, Saiyuuki)
7 Mapper 17 (Wing of Madoola)
D4 When A0=0: Select VRAM Page (?=BLK0, ?=BLK1)
When A0=1: ?Mirroring (0=Vertical, 1=Horizontal Mirroring)
D3-D0 Unknown (usually zero)
43FEh Memory Control (apparently independendly of current Mode) (?)
D7-D2 Select ?K ROM at 8000h-?
D1-D0 Select 8K VROM at PPU 0000h-1FFFh
43FFh Memory Control (as for current mode, ie. mirror of 8000h-FFFFh) (?)
4500h Configuration Register 2
D7-D6 FDS Mode (0=Disk/Load, 1=Reserved, 2=Cartridge, 3=Disk/Execute)
D5-D4 SRAM 6000h-7FFFh BANK "Present or Not" (0-3=?)
D3 SW Pin (maybe something related with above WE/SW selection)
D2-D0 PPU Mode Select (1or2?="*MODE" (32K), 5=256K, VRAM EXT, 7=256K)
|
| Mapper 6: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ |
Several hacked Japanese titles use this mapper, such as the hacked version of
Wai Wai World. The unhacked versions of these games seem to use a Konami VRC
mapper, and it's better to use them if possible.
8000h-FFFFh Memory Control (6bit)
Bit1-0 Select 8K VRAM (read/write-able) at PPU 0000h-1FFFh
Bit5-2 Select 16K ROM at 8000h-BFFFh (bank 0-0Fh)
N/A Fixed 16K ROM at C000h-FFFFh (always bank 7) (!)
|
Additional FFE registers:
Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches
| Mapper ?: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ |
10% of games declared as "Mapper 6" are this (and not Mapper 6).
8000h-FFFFh Memory Control (6bit)
Bit3-0 Select 16K ROM at 8000h-BFFFh
Bit5-4 Select 8K VROM at PPU 0000h-1FFFh
|
Lower bits are ROM bank, upper bits VROM bank, ie. vice-versa as Mapper 6.
Additional FFE registers:
Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches
| Mapper 7: AOROM - PRG/32K, Name Table Select |
Numerous games released by Rare Ltd. use this mapper, such as Battletoads,
Wizards & Warriors, and Solar Jetman.
8000h-FFFFh Memory Control
Bit2-0 Select 32K ROM bank at 8000h-FFFFh (initially 1st bank)
Bit4 One-Screen Name Table Select (0=BLK0, 1=BLK1)
Bit3,5-7 Not used
|
Uses a single 74LS161 chip (connection: /PRG-CLK, R/W-/LOAD). ANROM additionally uses a 74LS02 to enable ROM only when R/W=HIGH and /PRG=LOW.
Board NES-AOROM-03: 256K PRG ROM (8 banks) (32pin ROM) (with bus-conflicts)
Board NES-BNROM-01: 128K PRG ROM (4 banks) (28pin ROM) (with bus-conflicts)
Board NES-ANROM-03: 128K PRG ROM (4 banks) (28pin ROM) (without bus-conflicts)
All carts using it have 8K of VRAM at PPU 0000h.
Deadly Towers seems to be BNROM, using horizontal mirroring, instead Bit4?
| Mapper 8: FFE F3xxx - PRG/32K, VROM/8K, NT, IRQ |
Several hacked Japanese titles use this mapper, such as the hacked version of
Doraemon.
8000h-FFFFh Memory Control (same as GNROM, Mapper 66)
Bit1-0 Select 8K VROM (usually read-only) at PPU 0000h-1FFFh
Bit5-4 Select 32K ROM at 8000h-FFFFh (initially 1st bank)
|
Additional FFE registers:
Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches
| Mapper 9: MMC2 - PRG/24K/8K, VROM/4K, NT, LATCH |
Used only on by Punch-Out, and Mike Tyson's Punch-Out.
A000h-AFFFh Select 8K ROM at 8000h-9FFFh (initially 1st bank) N/A Fixed 24K ROM at A000h-FFFFh (always last three 8K banks) B000h-CFFFh Select 4K VROM at PPU 0000h-0FFFh D000h-DFFFh Select 4K VROM at PPU 1000h-1FFFh (used when latch=FDh) E000h-EFFFh Select 4K VROM at PPU 1000h-1FFFh (used when latch=FEh) F000h-FFFFh Mirroring Select (Bit0: 0=Vertical, 1=Horizontal mirroring) PPU 1FD0h-1FDFh Access to Pattern Table 0, Tile FDh --> sets latch=FDh PPU 1FE0h-1FEFh Access to Pattern Table 0, Tile FEh --> sets latch=FEh |
The latch contains FEh on reset. The latch is automatically written to on any access to PPU 1FD0h-1FEFh, which does usually happen when the PPU fetches bitmap data for Tile FDh or FEh from Pattern Table 1.
The latches might also get changed on access to PPU 0FD0h-0FEFh (?)
| Mapper 10: MMC4 - PRG/16K, VROM/4K, NT, LATCH |
Used only by Fire Emblem, Fire Emblem Gaiden, and Family War.
A000h-AFFFh Select 16K ROM bank at 8000h-BFFFh (initially 1st bank) N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank) B000h-BFFFh Select 4K VROM bank at PPU 0000h-0FFFh (used when latch0=FDh) C000h-CFFFh Select 4K VROM bank at PPU 0000h-0FFFh (used when latch0=FEh) D000h-DFFFh Select 4K VROM bank at PPU 1000h-1FFFh (used when latch1=FDh) E000h-EFFFh Select 4K VROM bank at PPU 1000h-1FFFh (used when latch1=FEh) F000h-FFFFh Mirroring Select (Bit0: 0=Vertical, 1=Horizontal mirroring) PPU 0FD0h-0FDFh Access to Pattern Table 0, Tile FDh --> sets latch0=FDh PPU 0FE0h-0FEFh Access to Pattern Table 0, Tile FEh --> sets latch0=FEh PPU 1FD0h-1FDFh Access to Pattern Table 1, Tile FDh --> sets latch1=FDh PPU 1FE0h-1FEFh Access to Pattern Table 1, Tile FEh --> sets latch1=FEh |
The latches contain FEh on reset. Latches are automatically written to on any access to PPU 0FD0h-0FEFh or 1FD0h-1FEFh, which does usually happen when the PPU fetches bitmap data for Tile FDh or FEh. The new latch setting is then used for all <further> tiles (tiles FDh/FEh are still fetched from the <old> latch setting).
| Mapper 11: Color Dreams - PRG/32K, VROM/8K |
This mapper is used on several unlicensed Color Dreams titles, including
Crystal Mines and Pesterminator. Not sure if their religious ("Wisdom Tree")
games use the same mapper or not.
8000h-FFFFh Memory Control
Bit3-0 Select 32K ROM bank at 8000h-FFFFh (initially 1st bank)
Bit7-4 Select 8K VROM bank at PPU 0000h-1FFFh (initially 1st bank)
|
Many games using this mapper are somewhat glitchy. Bus-conflicts.
Uses a single 74LS377 (8bit D flip-flop with clock enable).
| Mapper 12: FFE F6xxx - Not specified, NT, IRQ |
No info. Don't have a ROM-image.
Maybe this meant to be "Mapper ?",
Mapper ?: FFE F4xxx - PRG/16K, VROM/8K, NT, IRQ
Additional FFE registers:
Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches
| Mapper 13: CPROM - 16K VRAM |
Used by Videomation (a bitmap drawing program).
N/A Fixed 4K VRAM at PPU 0000h-0FFFh (always Bank 0) 8000h-FFFFh Select 4K VRAM at PPU 1000h-1FFFh (Bank 0-3) |
16K VRAM for 32x30 different BG tiles (plus 64 sprites). Bus-conflicts.
| Mapper 15: X-in-1 - PRG/32K/16K, NT |
Used by Contra 100-in-1 (fake multicart with less than 100 different games),
and hacked versions of Crazy Climber, Dragon Ball, and Mobile Suit (single
game carts).
8000h-FFFFh Memory Control (Decoded by address AND data lines)
D5-D0 Select 16K ROM Bank (X)
D6 Mirroring Control (0=Vertical, 1=Horizontal Mirroring)
D7 Select 8K ROM Bank (Y) (should be zero in non-8K-modes)
A1-A0 ROM Bank Mode (0=32K, 1=128K, 2=8K, 3=16K)
Mapping in different modes is:
8K Mode - Bank (X*2+Y) at each 8000h, A000h, C000h, E000h
16K Mode - Bank (X) at 8000h-BFFFh and (X) at C000h-FFFFh
32K Mode - Bank (X) at 8000h-BFFFh and (X OR 1) at C000h-FFFFh
128K Mode - Bank (X) at 8000h-BFFFh and LAST bank at C000h-FFFFh
|
Initially first 32K ROM selected. The cartridge contains 8K VRAM.
| Mapper 16: Bandai - PRG/16K, VROM/1K, IRQ, EPROM |
This mapper is used on several Japanese titles by Bandai, such as the
DragonBall Z series and the SD Gundam Knight series.
6000h,7FF0h,8000h Select 1K VROM at PPU 0000h-03FFh
6001h,7FF1h,8001h Select 1K VROM at PPU 0400h-07FFh
6002h,7FF2h,8002h Select 1K VROM at PPU 0800h-0BFFh
6003h,7FF3h,8003h Select 1K VROM at PPU 0C00h-0FFFh
6004h,7FF4h,8004h Select 1K VROM at PPU 1000h-13FFh
6005h,7FF5h,8005h Select 1K VROM at PPU 1400h-17FFh
6006h,7FF6h,8006h Select 1K VROM at PPU 1800h-1BFFh
6007h,7FF7h,8007h Select 1K VROM at PPU 1C00h-1FFFh
6008h,7FF8h,8008h Select 16K ROM at 8000h-BFFFh (initially 1st bank)
N/A Fixed 16K ROM at C000h-FFFFh (always last bank)
6009h,7FF9h,8009h Mirroring/Page Select (Bit1-0)
0 Two-Screen Vertical mirroring
1 Two-Screen Horizontal mirroring
2 Single-Screen BLK0
3 Single-Screen BLK1
600Ah,7FFAh,800Ah IRQ Control Register (Bit 0)
0 Disable/Acknowledge IRQ
1 Enable IRQ
600Bh,7FFBh,800Bh Low byte of IRQ counter
600Ch,7FFCh,800Ch High byte of IRQ counter
600Dh,7FFDh,800Dh EPROM I/O Port - I am not sure how this works.
|
The IRQ counter is decremented each clock cycle if active, and set off when it reaches zero. An IRQ interrupt is executed at that point.
| Mapper 17: FFE F8xxx - PRG/8K, VROM/1K, NT, IRQ |
Several hacked Japanese titles use this mapper, such as the hacked versions
of Parodius and DragonBall Z 3.
4504h Select 8K ROM at 8000h-9FFFh (initially 1st half of 1st 16K) 4505h Select 8K ROM at A000h-BFFFh (initially 2nd half of 1st 16K) 4506h Select 8K ROM at C000h-DFFFh (initially 1st half of last 16K) 4507h Select 8K ROM at E000h-FFFFh (initially 2nd half of last 16K) 4510h Select 1K VROM at PPU 0000h-03FFh 4511h Select 1K VROM at PPU 0400h-07FFh 4512h Select 1K VROM at PPU 0800h-0BFFh 4513h Select 1K VROM at PPU 0C00h-0FFFh 4514h Select 1K VROM at PPU 1000h-13FFh 4515h Select 1K VROM at PPU 1400h-17FFh 4516h Select 1K VROM at PPU 1800h-1BFFh 4517h Select 1K VROM at PPU 1C00h-1FFFh |
Additional FFE registers:
Mapper 6,8,12,17: Front Far East (FFE) Configuration, IRQs, Patches
| Mapper 18: Jaleco SS8806 - PRG/8K, VROM/1K, NT, IRQ, EXT |
This mapper is used on several Japanese titles by Jaleco, such as Baseball 3,
Lord of Kings, etc.
8000h/8001h Select 8K ROM at 8000h-9FFFh (Lower/Upper 4bits)
8002h/8003h Select 8K ROM at A000h-BFFFh (Lower/Upper 4bits)
9000h/9001h Select 8K ROM at C000h-DFFFh (Lower/Upper 4bits)
N/A Fixed 8K ROM at E000h-FFFFh (always last bank)
9002h Battery Back SRAM (Bit0: 0=Enable, 1=Disable)
(unused by Lord of Kings)
9003h Unknown
(used by Lord of Kings)
A000h/A001h Select 1K VROM at PPU 0000h-03FFh (Lower/Upper 4bits)
A002h/A003h Select 1K VROM at PPU 0400h-07FFh (Lower/Upper 4bits)
B000h/A001h Select 1K VROM at PPU 0800h-0BFFh (Lower/Upper 4bits)
B002h/A003h Select 1K VROM at PPU 0C00h-0FFFh (Lower/Upper 4bits)
C000h/C001h Select 1K VROM at PPU 1000h-13FFh (Lower/Upper 4bits)
C002h/C003h Select 1K VROM at PPU 1400h-17FFh (Lower/Upper 4bits)
D000h/D001h Select 1K VROM at PPU 1800h-1BFFh (Lower/Upper 4bits)
D002h/D003h Select 1K VROM at PPU 1C00h-1FFFh (Lower/Upper 4bits)
E000h/E001h Lower 8bit of decrementing 16bit IRQ counter (Lower/Upper 4bits)
E002h/E003h Upper 8bit of decrementing 16bit IRQ counter (Lower/Upper 4bits)
F000h IRQ Control Register 0
Bit0 Maybe 1=Load Counter?
F001h IRQ Control Register 1
Bit0 IRQ Enable (0=Disabled, 1=Enable)
Bit1-3 IRQ Counter Width (0=16bit, 1=12bit, 2-3=8bit, 4-7=4bit)
With widths less than 16bit, underflows recurse only lower counter bits.
F002h Name Table Select (2bit)
0 Two-Screen, Horizontal Mirroring
1 Two-Screen, Vertical Mirroring
2-3 Single-Screen BLK0
F003h Unused (or an External I/O Port which is unused?)
|
| Mapper 19: Namcot 106 - PRG/8K, VROM/1K/VRAM, IRQ, SOUND |
This mapper is used on several Japanese titles by Namcot, such as
Splatterhouse and Family Stadium '90.
Pattern Table Control
8000h-87FFh Select 1K VROM at PPU 0000h-03FFh (with E800h/Bit6)
8800h-8FFFh Select 1K VROM at PPU 0400h-07FFh ("")
9000h-97FFh Select 1K VROM at PPU 0800h-0BFFh ("")
9800h-9FFFh Select 1K VROM at PPU 0C00h-0FFFh ("")
A000h-A7FFh Select 1K VROM at PPU 1000h-13FFh (with E800h/Bit7)
A800h-AFFFh Select 1K VROM at PPU 1400h-17FFh ("")
B000h-B7FFh Select 1K VROM at PPU 1800h-1BFFh ("")
B800h-BFFFh Select 1K VROM at PPU 1C00h-1FFFh ("")
|
The upper two bits Port E800h-EFFFh are used to select VROM/VRAM mode (mind that the lower six bits of that port Select 8K ROM at A000h-BFFFh).
E800h, Bit6 VROM/VRAM Mode for PPU 0000h-0FFFh (0=VROM+VRAM, 1=VROM-Only) E800h, Bit7 VROM/VRAM Mode for PPU 1000h-1FFFh (0=VROM+VRAM, 1=VROM-Only) |
In VROM-Only mode, VROM banks 0-FFh can be selected. In VROM+VRAM mode only VROM banks 0-DFh can be selected, and values E0h-FFh select VRAM.
Name Table Control
C000h-C7FFh Select 1K VROM/VRAM at PPU 2000h-23FFh (E0h and up = VRAM) C800h-CFFFh Select 1K VROM/VRAM at PPU 2400h-27FFh (E0h and up = VRAM) D000h-D7FFh Select 1K VROM/VRAM at PPU 2800h-2BFFh (E0h and up = VRAM) D800h-DFFFh Select 1K VROM/VRAM at PPU 2C00h-2FFFh (E0h and up = VRAM) |
Only VROM banks 0-DFh can be selected, and values E0h-FFh activate internal VRAM, Bit0 of the bank number is then used to select BLK0 or BLK1.
CPU Memory Control
E000h-E7FFh Select 8K ROM at 8000h-9FFFh (initially 1st half of 1st 16K)
Bit5-0 Page_number
E800h-EFFFh Select 8K ROM at A000h-BFFFh (initially 2nd half of 1st 16K)
Bit5-0 Page_number
Bit6 Select at CHR_address $0000-$0FFF 0:ROM&RAM 1:ROM
Bit7 Select at CHR_address $1000-$1FFF 0:ROM&RAM 1:ROM
F000h-F7FFh Select 8K ROM at C000h-DFFFh (initially 1st half of last 16K)
Bit5-0 Page_number
N/A Fixed 8K ROM at E000h-FFFFh (always 2nd half of last 16K)
|
The lower 6bit of these registers specify ROM bank numbers. Caution: The upper 2bit of E800h-EFFFh are used to select Pattern Table VROM/VRAM Mode.
IRQ Control
5000h-57FFh Bit7-0: Lower 8bit of 15bit IRQ counter (R/W) (!)
5800h-5FFFh Bit6-0: Upper 7bit of 15bit IRQ counter (R/W) (!)
Bit7: 0=Disable IRQs, 1=Enable IRQs
|
The IRQ counter is incremented each clock cycle, an IRQ is generated when it overflows (at 7FFFh, since it's a 15bit value). Sangokushi 2 uses IRQs, but many other Namcot games don't use IRQs.
Sound Control
4800h Expand I/O Data Register
F800h Expand I/O Address Register
Bit7 Auto Increment (0=Disable, 1=Enable)
Bit6-0 Address (00h-7Fh)
|
Index Addresses: (Dots "..." = Japanese text, not translated)
00h-3Fh See NAMCO.TXT, Japanese (.............)
40h,48h,50h,58h,60h,68h,70h,78h Channel 1-8, Frequency Lower 8bit
41h,49h,51h,59h,61h,69h,71h,79h See NAMCO.TXT, Japanese (......)
42h,4Ah,52h,5Ah,62h,6Ah,72h,7Ah Channel 1-8, Frequency Middle 8bit
43h,4Bh,53h,5Bh,63h,6Bh,73h,7Bh See NAMCO.TXT, Japanese (......)
44h,4Ch,54h,5Ch,64h,6Ch,74h,7Ch Channel 1-8, Frequency Upper 2bit & Option
Bit7-5 Not used
Bit4-2 VVV: 8-(....)(... 2byte) ..: VVV=000... 16byte,VVV=100..8byte....
Bit1-0 Frequency Upper 2bit
45h,4Dh,55h,5Dh,65h,6Dh,75h,7Dh See NAMCO.TXT, Japanese (......)
46h,4Eh,56h,5Eh,66h,6Eh,76h,7Eh Channel 1-8, Offset Address (00h-3Fh)
Bit7-1 AAAAAAA [6bit address stored in a 7bit value?]
Bit0 Not used
47h,4Fh,57h,5Fh,67h,6Fh,77h,7Fh Channel 1-8
Bit7-4 ????: 7...(kingofkings),3...
Bit3-0 VVVV: ....
|
Frequency: 0=Lowest, 3FFFFh=Highest.
According to Gorohs frequency table, Tone "C" of Octave "1-8" is: 1:47Eh,
2:8FBh, 3:11F6h, 4:23ECh, 5:47DAh, 6:8FB3h, 7:11F66h, 8:23ECCh.
According to my CPC frequency table, middle "C" of octave "0" should be
261.626Hz. No idea how to match that into a formula.
| Mapper 20: Disk System - PRG RAM, BIOS, DISK, IRQ, SOUND |
Used by Famicom Disk System only.
Famicom Disk System (FDS)
| Mapper 21: Konami VRC4A/VRC4C - PRG/8K, VROM/1K, NT, IRQ |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 22: Konami VRC2A - PRG/8K, VROM/1K, NT |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 23: Konami VRC2B/VRC4E - PRG/8K, VROM/1K, NT, (IRQ) |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 24: Konami VRC6A - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 25: Konami VRC4B/VRC4D - PRG/8K, VROM/1K, NT, IRQ |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 26: Konami VRC6B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND |
Mapper 21-26,73,75,85: Konami VRC Mappers
VRC6 Sound Registers
Two Rectangle channels with 4bit volume levels each, one Saw channel with
5bit volume level. These are added into a 6bit output level, and then merged
with normal Famicom sound signal.
9000h/A000h - Channel 1/2 - Square Volume/Duty
Bit7-4 Duty Cycle bits:
0000 - 1/16 "-_______________-_______________" ( 6.25%)
0001 - 2/16 "--______________--______________" (12.50%)
0010 - 3/16 "---_____________---_____________" (18.75%)
0011 - 4/16 "----____________----____________" (25.00%)
0100 - 5/16 "-----___________-----___________" (31.25%)
0101 - 6/16 "------__________------__________" (37.50%)
0110 - 7/16 "-------_________-------_________" (43.75%)
0111 - 8/16 "--------________--------________" (50.00%)
1xxx - 16/16 "--------------------------------" (100.00%)
Bit3-0 Linear Volume (0=Silence, 0Fh=Loudest)
|
100% Duty can be used as digitized mode, the channel permanently outputs high level, ie. the current volume setting, and isn't affected by the frequency registers.
B000h - Channel 3 - Saw Volume Step
Bit7-6 Not used Bit5-0 Volume Step (V) (0..2Ah=Silent..Loudest) (2Bh..3Fh=Wraps/Garbage) |
The overall output looks like "//////" whereas each "/" is split into 7 steps, the output level on step 1-7 is calculated as such:
FOR I=1 to 7 ;step 1-7
IF I=1 THEN X=0 ;reset to 0 in 1st step
ELSE X=(X+V) AND FFh ;add accumulator
Output=(X/8) ;output upper 5bit of X
NEXT
|
Note: X is an 8bit value, and wraps on overflow, ie. if V>2Ah.
9001h/A001h/B001h - Channel 1/2/3 - Frequency LSB
Bit7-0 Lower 8 bits of frequency data |
9002h/A002h/B002h - Channel 1/2/3 - Frequency MSB
Bit7 Channel disable (0=Disable, 1=Enable) Bit6-4 Not used Bit3-0 Upper 4 bits of frequency data |
To calculate output frequency:
Channel 1/2: F=1.79MHz/16/(N+1) ;16-step duty cycles Channel 3: F=1.79MHz/14/(N+1) ;7-step phases |
| Mapper 21-26,73,75,85: Konami VRC Mappers |
This chapter describes all known VRC variants. The different Port addresses
are specified as X.Y.Z which may look a bit abstract at the first glance, at
second glance it should be easier to understand as than using separate
chapters for each of the 13 variants.
VRC Chip Versions
Type PRG Bank VROM Banks NT IRQ Sound VRC1 PRG/8K VROM/4K NT - - VRC2 PRG/8K VROM/1K NT - - VRC3 PRG/16K VRAM IRQ - VRC4 PRG/8K VROM/1K NT IRQ - VRC6 PRG/16K/8K VROM/1K NT IRQ SOUND VRC7 PRG/16K/8K VROM/1K NT IRQ SOUND |
For most chips, there are different connection variants, VRC2a, VRC2b, etc.
VRC Data Bus
VRC1, VRC2, and VRC3 use a 4bit data bus, connected to D3-D0, any 8bit
registers are thus split into two 4bit ports. VRC4 seems to have an
additional D4 pin, which is used only for 5bit PRG ROM banks. VRC6 and VRC7
have a full 8bit data bus.
VRC Address Bus
Most VRCs have a 6bit address bus, described here as X.Y.Z - the upper four
address bits are always A15-A12 (X), however, the connection of the lower two
address bits (Y and Z) varies. VRC7 normally uses only X.Y bits (only the
Sound registers use X.Y.Z). VRC1/VRC3 uses only the X address bits. A15
serves as chip select, and must be HIGH for all VRC registers.
VRC Connection Variants of Lower two bits of X.Y.Z addresses
Mapper Y Z Used by
75 VRC1 - - Ganbare Goemon 1, Junior Basket - Two on Two, King Kong 2,
Exciting Boxing, Jajamaru Ninpou Chou, Tetsuwan Atom
22 VRC2a A0 A1 Twin Bee 3, Ganbare Pennant Race
23 VRC2b A1 A0 Wai Wai World 1, Getsufuu Maden, Kaiketsu Yanchamaru 2
Dragon Scroll, Gryzor/Contra, Jarinko Chie, Ganbare Goemon
73 VRC3 - - Salamander
21 VRC4a A2 A1 Wai Wai World 2
21 VRC4c A7 A6 Ganbare Goemon Gaiden 2
25 VRC4b A0 A1 Bio Miracle Bokutte Upa, Ganbare Goemon Gaiden, Gradius 2,
Racer Mini Yonku
25 VRC4d A2 A3 Teenage Mutant Hero Turtles 1+2, Goal!!
23 VRC4e A3 A2 Parodius da!, Akumajou Special, Crisis Force,
Tiny Toon Adventures 1, Moe Pro!
24 VRC6a A1 A0 Akumajou Densetsu (Castlevania 3)
26 VRC6b A0 A1 Esper Dream 2, Mouryou Senki Madara
85 VRC7 A4 (A5) Lagrange Point (Z=A5 used for Sound only)
85 VRC7b A3 (?) Tiny Toon Adventures 2 (no Sound - maybe not a VRC7 ?)
|
Note that most mapper numbers are shared for two different connection variants, mapper 23 is even shared for different chip versions, the unused address bits are usually zero, so that software and hardware could, for example, reproduce Z=(A0 OR A2) for mapper 23.
VRC2a variant uses VROM bank outputs Bit1-7, all other VRCs use Bit0 and up.
PRG ROM Bank Registers (decoded by X or X.Y parts of the X.Y.Z address)
VRC1 VRC2 VRC3 VRC4 VRC6 VRC7 Expl. - - F - 8 - Select 16K ROM at 8000h-BFFFh 8 8 - 8 - 8.0 Select 8K ROM at 8000h-9FFFh A A - A - 8.1 Select 8K ROM at A000h-BFFFh C - - - C 9.0 Select 8K ROM at C000h-DFFFh - FIX FIX FIX - - Fixed 8K ROM at C000h-DFFFh (last-1 8K) FIX FIX FIX FIX FIX FIX Fixed 8K ROM at E000h-FFFFh (last-0 8K) |
The 16K banks of VRC3/VRC6 are Linear Addresses divided by 16K (not by 8K).
VRC4 can swap 8000h-9FFFh and C000h-DFFFh, see VRC4 Memory Control below.
VROM Bank Registers (VRC2,VRC4=2x4bit LSB/MSB, VRC6,VRC7=8bit)
VRC2,4 VRC6 VRC7 Expl. B.0.0/1 D.0.0 A.0 Select 1K VROM bank at PPU 0000h-03FFh B.1.0/1 D.0.1 A.1 Select 1K VROM bank at PPU 0400h-07FFh C.0.0/1 D.1.0 B.0 Select 1K VROM bank at PPU 0800h-0BFFh C.1.0/1 D.1.1 B.1 Select 1K VROM bank at PPU 0C00h-0FFFh D.0.0/1 E.0.0 C.0 Select 1K VROM bank at PPU 1000h-13FFh D.1.0/1 E.0.1 C.1 Select 1K VROM bank at PPU 1400h-17FFh E.0.0/1 E.1.0 D.0 Select 1K VROM bank at PPU 1800h-1BFFh E.1.0/1 E.1.1 D.1 Select 1K VROM bank at PPU 1C00h-1FFFh |
Note that VRC2A uses Bit7-1 of the 2x4bit register, VRC2B uses Bit6-0, VRC4 and up use Bit6-0 (or all bits, Bit7-0, for large VROMs).
Lagrange Point contains VRAM instead VROM, the VRAM <is> map-able.
Salamander (VRC3) contains VRAM, which appears to be <not> map-able.
VRC1 VROM Bank Registers (5bit values, split into 4+1 bits)
9 Bit0: Mirroring, Bit1-2: MSBs of VROM banks, Bit3: Unused/zero E Lower 4bit of 4K VROM bank at PPU 0000h-0FFFh (MSB in Bit1 of Register 9) F Lower 4bit of 4K VROM bank at PPU 1000h-1FFFh (MSB in Bit2 of Register 9) |
IRQ Registers (VRC1,VRC2=N/A, VRC3,VRC4=2x4bit, VRC6,VRC7=8bit)
VRC4 VRC6 VRC7 VRC3 Expl. F.0.0/1 F.0.0 E.1 A/B IRQ Reload value F.1.0 F.0.1 F.0 C IRQ Control (Bit0: 0=Disable, Bit1: 0=One-Shot) F.1.1 F.1.0 F.1 D IRQ Acknowledge (write any value to this address) |
IRQ Reload is loaded to actual counter on write to IRQ Control Register, and on Counter overflow. If IRQ Control Regiser Bit1 is set, then the counter is automatically Restarted and Reloaded on Overflow.
The IRQ counter is incremented each 113.75 cycles (or each 114 cycles?),
which is almost exactly once per NTSC-scanline, including for "hidden"
scanlines during VBlank (only exception is VRC3, which is incremented every
256 cycles).
Mind that PAL/NTSC have different VBlank/Hblank times, and so, need different
counter values. The VRC4 games Goal! and Moe Pro! appear to be bugged pirate
ports from original Jaleco mapper to Konami-style mapper, these games do
incorrectly acknowledge IRQs by writing zero to the IRQ Control register
rather than by writing any value to the IRQ Acknowledge register, not sure if
that works on real VRC4 hardware.
VRC4 Memory Control (VRC4 only - not VRC2,6,7)
9.0.1 (or 9.1.0?) Memory Control (2bit) |
Bit1: PRG ROM Swap (0=Normal, 1=Swap) When swapped: Port 8.0.0 controls ROM at C000h-DFFFh, and ROM at 8000h-9FFFh becomes fixed, containing the 1st half of <last> 16K.
Bit0: Enable SRAM at 6000h-7FFFh (0=Disable, 1=Enable), VRC6 is having an
equivalent function Bit7 of Name Table Control register.
Name Table Control
VRC1 VRC2,4 VRC6 VRC7 Expl. 9 9.0.0 B.1.1 E.0 Mirroring/Page Select |
Mirroring selection VRC2,VRC4,VRC7: Bit1-0, VRC6: Bit3-2, VRC1: Bit0:
0 Two-Screen Vertical mirroring (VRC1: Register 9, Bit0=0) 1 Two-Screen Horizontal mirroring (VRC1: Register 9, Bit0=1) 2 Single-Screen BLK1 (VRC1: N/A) 3 Single-Screen BLK0 (VRC1: N/A) |
On VRC6, bit5 additionally inverts the BLK-outputs, BLK0 then becomes BLK1, and vice versa, that also applies in Two-Screen modes, ie. the upper-left name table may be either BLK1 or BLK0.
And, on VRC6, Bit7 controls SRAM (0=Disable, 1=Enable).
VRC6 Sound Registers
Mapper 26: Konami VRC6B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND
VRC7 OPL2 Sound Registers
9.1.0 Index Register 9.1.1 Data Register Mapper 85: Konami VRC7A/B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND |
Unknown Registers
VRC3 - Salamander writes 00h to Port 8000h and 9000h.
| Mapper 32: Irem G-101 - PRG/8K, VROM/1K, NT |
This mapper is used on several Japanese titles by Irem, such as ImageFight 2.
9FFFh Control Register (Bit1,0)
Bit0 - Name Table ?Mirroring (0=Horizontal, 1=Vertical Mirroring)
Bit1 - Port 8FFFh Switching Mode (see above)
8FFFh When 9FFFh/Bit1=0:
Select 8K ROM bank at 8000h-9FFFh (initially 1st 8K bank)
Fixed 8K ROM bank at C000h-DFFFh (always 1st half of last 16K)
When 9FFFh/Bit1=1:
Fixed 8K ROM bank at 8000h-9FFFh (always 1st 8K bank)
Select 8K ROM bank at C000h-DFFFh (initially probably 9FFFh/Bit1=0)
AFFFh Select 8K ROM bank at A000h-BFFFh (initially 2nd 8K bank)
N/A Fixed 8K ROM bank at E000h-FFFFh (always last 8K bank)
BFF0h Select 1K VROM bank at PPU 0000h-03FFh
BFF1h Select 1K VROM bank at PPU 0400h-07FFh
BFF2h Select 1K VROM bank at PPU 0800h-0BFFh
BFF3h Select 1K VROM bank at PPU 0C00h-0FFFh
BFF4h Select 1K VROM bank at PPU 1000h-13FFh
BFF5h Select 1K VROM bank at PPU 1400h-17FFh
BFF6h Select 1K VROM bank at PPU 1800h-1BFFh
BFF7h Select 1K VROM bank at PPU 1C00h-1FFFh
|
| Mapper 33: Taito TC0190/TC0350 - PRG/8K, VROM/1K/2K, NT, IRQ |
Used by Don Doko Don I, II, Flintstones - Rescue of Dino & Hoppy, Bakushou
Jinsei Gekijou I, II, III, Insector X, Operation Wolf, Power Blazer, Golf Ko
Open, Akira, Takeshi no Sengoku Fuuunji, Jetsons - Cogswell's Caper, Bubble
Bobble 2, Captain Saver.
TC0190 and TC0350 are slightly different, one has IRQs, one doesn't. No idea
which is which, so they'll be referenced as Type I and II.
Type I and II - Memory Banking Registers
8000h Select 8K ROM bank at 8000h-9FFFh (Type I: Bit6=Mirroring, see below) 8001h Select 8K ROM bank at A000h-BFFFh N/A Fixed 16K ROM bank at C000h-FFFFh (always last 16K) 8002h Select 2K VROM bank at PPU 0000h-07FFh 8003h Select 2K VROM bank at PPU 0800h-0FFFh A000h Select 1K VROM bank at PPU 1000h-13FFh A001h Select 1K VROM bank at PPU 1400h-17FFh A002h Select 1K VROM bank at PPU 1800h-1BFFh A003h Select 1K VROM bank at PPU 1C00h-1FFFh |
Type I - Mirroring
8000h Bit4-0:See above, Bit6:Mirroring (0=Vertical, 1=Horizontal Mirroring) |
Ignore this bit if Type II registers are used.
Type II - Mirroring and IRQ
C000h IRQ Counter (incremented every scanline, paused during VBlank) C001h IRQ Related (write same value as to C000h) C002h IRQ Start/Enable (write any value) C003h IRQ Acknowledge/Stop (write any value) E000h Mirroring (Bit6) (0=Vertical, 1=Horizontal Mirroring) E001h,E002h,E003h Unknown |
| Mapper 34: Nina-1 - PRG/32K, VROM/4K |
Used by Impossible Mission II.
7FFEh Select 4K VROM bank at PPU 0000h-0FFFh (4bit) 7FFFh Select 4K VROM bank at PPU 1000h-1FFFh (4bit) 7FFDh Select 32K ROM bank at 8000h-FFFFh (1bit) (initially 1st bank) |
Contains 8K WRAM at 6000h-7FFFh (not sure if last three bytes can be used).
Uses six TTL chips, 2x74LS173, 74LS139, 74LS133, 74LS74, and 74LS00, and a
faux-lockout chip labelled 'NINA'.
| Mapper 40: FDS-Port - Lost Levels |
Used by Super Mario Bros 2 - Lost Levels.
8000h-9FFFh Disable/Reset IRQ counter (by writing any value) A000h-BFFFh Enable/Start IRQ counter (by writing any value) C000h-DFFFh Not Used N/A Fixed 8K ROM at 6000h-7FFFh (always bank 6) N/A Fixed 8K ROM at 8000h-9FFFh (always bank 4) N/A Fixed 8K ROM at A000h-BFFFh (always bank 5) E000h-FFFFh Select 8K ROM at C000h-DFFFh N/A Fixed 8K ROM at E000h-FFFFh (always bank 7, ie. last bank) |
When enabled, IRQ generated after 4096 clock cycles (about 36 scanlines).
Uses different ports, but the features are about same as:
Mapper 50: FDS-Port - Alt. Levels
| Mapper 41: Caltron 6-in-1 |
Used by Caltron 6-in-1 cartridge only.
6000h-67FFh Main Control Register (decoded by ADDRESS lines A0-A5)
A2-A0 Select 32K ROM at 8000h-FFFFh
A2 MSB of above bank number - also enables second register
A4-A3 Upper two bits of 8K VROM bank at 0000h-1FFFh
A5 Name Table (0=Vertical, 1=Horizontal Mirroring)
8000h-FFFFh Auxilary CHR control (decoded by DATA lines D0-D1)
This register is write-protected when above A2=0 (!)
D1-D0 Lower two bits of 8K VROM bank at 0000h-1FFFh
|
When the NES is switched on, or the reset button is pressed, both registers are cleared to 00h, done by a cool little diode / RC circuit on the PHI2 line.
| Mapper 42: FDS-Port - Mario Baby |
Used only by one game: A pirate copy of Bio Miracle Boukette Upa, renamed to
Mario Baby, and modified to work as cartridge (instead FDS floppy disk).
E000h-FFFCh Select 8K ROM at 6000h-7FFFh N/A Fixed 32K ROM at 8000h-FFFFh (always last 32K) E001h-FFFDh Select mirroring (Bit3: 0=Vertical, 1=Horizontal Mirroring) E002h-FFFEh IRQ Control (Bit1: 0=Disable/Reset, 1=Enable/Start) E003h-FFFFh Not used |
When enabled, IRQ generated after 24576 clock cycles (about 216 scanlines).
These ports are mirrored from E000h-FFFFh, every 4 bytes.
Consists of a whopping 11 chips - 9 TTL/CMOS, 8K RAM, and 128K ROM.
Mapper number 42 is also assigned to Ai Senshi Nicol. In short, doing this:
8000h Select 8K VROM at PPU 0000h-1FFFh F000h Select 8K ROM at 6000h-7FFFh N/A Fixed 32K ROM at 8000h-FFFFh (always last 32K) |
However, it is doing some odd initialization, writing to Port E000h (index, 1-5 used), and Port F000h (data for index 1-5, looks like 8K ROM banks at 8000h, A000h, C000h, 6000h, E000h). Note that: A) the last 32K seem to be always mapped to 8000h-FFFFh. B) each final write to F000h seems to be done with index 4. If that behaviour doesn't change later on in the game, then Port F000h (or even E000h) could be interpreted exactly as for Mario Baby.
| Mapper 43: X-in-1 |
Used by 150-in-1 (a fake containing 56 games, plus some cheat modes, chip 0
is 1024K, chip 1 is 512K, chip 2-3 are not installed).
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A7-A0 Select 32K ROM Bank (From currently selected Chip)
A9-A8 Select ROM Chip (Empty bus if selected chip not installed)
A10 Not used (Always zero)
A11 Bank Mode (0=32K, 1=16K; Lower/Upper half via A12)
A12 Select 16K ROM Bank (0=Lower, 1=Upper) (Should be zero in 32K mode)
A13 Mirroring (0=Vertical, 1=Horizontal Mirroring)
A14 Not used (Always zero)
|
Initially 1st 32K selected. The cartridge includes 8K VRAM.
| Mapper 44: 7-in-1 MMC3 Port A001h |
Used by Super Big 7-in-1.
A001h - Select 128K ROM/VROM Block (0..5) or last 256K ROM/VROM Block (6) |
Block 0 seems to be required on power-up.
The rest of both mappers is same as MMC3 (for the selected block of memory),
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 45: X-in-1 MMC3 Port 6000hx4 |
Used in Super 3-in-1, Super 4-in-1, Super 8-in-1, Hero 8-in-1, Super 13-in-1,
and 1000000-in-1 (a fake with 1000000 duplicated/nonsense titles).
Configuration value initialized by each FOUR writes to Port 6000h.
6000h 1st write - Configuration Bits 0-7 6000h 2nd write - Configuration Bits 8-15 6000h 3nd write - Configuration Bits 16-23 6000h 4th write - Configuration Bits 24-31 |
The meaning of the 32 configuration bits is:
Bit7-0 VROM base in 1K steps Bit15-8 ROM base in 8K steps Bit19-16 VROM mask in 1K steps, Mask=(2 SHL (X AND 7))+(X AND 8)/8 Bit23-20 VROM base in 256K steps Bit29-24 ROM mask in 8K steps, Mask=(3Fh AND (NOT X)) Bit30 LOCK (set when menu selection completed, probably locks Port 6000h) Bit31 ??? |
Memory selections are Bank=((Mmc3Bank AND ConfigMask) OR ConfigBase). For MMC3 Registers 0 and 1 (map 2x1K banks), above formula applies to both banks, ie. VROM Mask=0 maps same 1K bank twice (instead two continous 1K banks).
128K Block 3 seems to be required on power-up, ie. the entry point is at the
end of 512K ROMs, or in the middle of 1024K ROMs. The MMC3 Port A001h
apparently can write-protect Port 6000h (just like it disables SRAM at
6000h-7FFFh). At least some carts have at least 2K SRAM (Mario 3 in Super
8-in-1 uses RAM at 7800h-7FFFh).
The rest of the mapper is same as MMC3 (for the selected block of memory),
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 46: 15-in-1 Color Dreams |
Used by Rumble Station 15-in-1, which contains 15 Color Dreams games.
6000h-7FFFh Multicart Memory Control
Bit0-3 Select 64K ROM Block (initially 1st bank) (always same as below)
Bit4-7 Select 64K VROM Block (initially 1st bank) (always same as above)
8000h-FFFFh Memory Control (selection within current 64K block)
Bit1 Select 32K ROM bank at 8000h-FFFFh (initially 1st bank)
Bit6-4 Select 8K VROM bank at PPU 0000h-1FFFh (initially 1st bank)
|
Port 8000h-FFFFh is same as Mapper 11, except that it is limited to 64K, and except that it doesn't seem to have bus-conflicts (the menu always uses Port 8888h, regardless of underlaying ROM content).
In some games ROM/VROM is less than 64K, so some memory areas are unused.
Mapper 11: Color Dreams - PRG/32K, VROM/8K
| Mapper 47: 2-in-1 MMC3 Port 6000h |
Used by 2-in-1 cart "Super Spike V'Ball + Nintendo World Cup".
6000h Select 1st or 2nd half of ROM/VROM (0 or 1) |
The rest of the mapper is same as MMC3 (for the selected block of memory),
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
The cartridge doesn't have SRAM, but the MMC3 Port A001h apparently can
write-protect Port 6000h (just like it could disable SRAM at 6000h-7FFFh).
| Mapper 48: Taito TC190V |
Reportedly "Tatio TC190V" used by "FlintStone".
Sounds like the Type II (or Type I?) variant of Mapper 33:
Mapper 33: Taito TC0190/TC0350 - PRG/8K, VROM/1K/2K, NT, IRQ
| Mapper 49: 4-in-1 MMC3 Port 6xxxh |
Used by Super HIK 4-in-1.
ROM/VROM are split into 128K blocks each, done as such:
[6000h]=01h ;init [6800h]=00h ;game 0 + [6808h]=08h crashes ? [6841h]=41h ;game 1 [6881h]=81h ;game 2 [68C1h]=C1h ;game 3 |
The rest of the mapper is same as MMC3 (for the selected block of memory),
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
The cartridge doesn't have SRAM, but the MMC3 Port A001h apparently can
write-protect Ports at 6000h-7FFFh (just like it could disable SRAM at
6000h-7FFFh).
| Mapper 50: FDS-Port - Alt. Levels |
Used by Super Mario Bros 2 - Alt. Levels.
4022h Select 8K ROM at C000h-DFFFh
Bit0 and/or Bit3 ZERO Bank 0
Bit0 and/or Bit3 SET Bank 0Ch (or maybe INCREMENT bank number?)
Other Bits Unknown
4122h IRQ Control
Bit0 and/or Bit1 ZERO Disable/Acknowledge
Bit0 and/or Bit1 SET Enable/Start
N/A Fixed 8K ROM at 6000h-7FFFh (always bank 0Fh, ie. last bank)
N/A Fixed 8K ROM at 8000h-9FFFh (always bank 08h)
N/A Fixed 8K ROM at A000h-BFFFh (always bank 09h)
N/A Fixed 8K ROM at E000h-FFFFh (always bank 0Bh)
|
When enabled, IRQ generated after 4096 clock cycles (about 36 scanlines).
Uses different ports, but the features are about same as:
Mapper 40: FDS-Port - Lost Levels
| Mapper 51: 11-in-1 |
Used by 11-in-1, containing ball games, like "soccer ball", and "golf ball".
6000h Mode Register
Bit1 ROM Block Size (0=128K Mode, 1=32K Mode)
Bit4 Unknown
8000h Base Address in 32K Steps (X) (0-0Fh)
32K Mode: Select 32K Bank (X) at 8000h-FFFFh (initially 1st 32K bank)
128K Mode: Select 16K Bank (X*2 OR 07h) at C000h-FFFFh
And: Select 8K Bank (X*4 OR 23h) at 6000h-7FFFh (for FDS ports)
C000h Lower 16K Select (Y) (0-1Fh) (128K Mode only, UNROM-style)
128K Mode: Select 16K Bank (Y*2 OR Y/10h) at 8000h-BFFFh
|
The cartridge does have 8K VRAM, even though there's a ROM-image around in which somebody has incorrectly included a copy of above 8K VRAM as "8K VROM".
| Mapper 52: 7-in-1 MMC3 Port 6800h with SRAM |
Used by Mario Party 7-in-1 (or short, Mari7in1).
"It's MMC3 and an extra bank control register. There is 1Mbyte of PRG ROM and
1Mbyte of CHR ROM on this cart. Interestingly, all the games appear to be
NTSC, except SMB2. For some reason, this is the PAL version! It consists of 1
6264 8K RAM chip (for WRAM), and 3 glop-tops. 2 are 1Mbyte ROMs while the
remaining chip is the mapper."
6800h Bank Control Byte
Bit7 Not used
Bit6 VROM Bank Size (0=256K, 1=128K)
Bit5,2,4 VROM 128K Bank (Bit4 not used in 256K CHR mode)
Bit3 PRG ROM Bank Size (0=256K, 1=128K)
Bit2,1,0 PRG ROM 128K Bank (Bit0 not used in 256K PRG mode)
|
Note: Bit2 is both MOST significant PRG bit, and MIDDLE significant CHR bit.
After a reset, this register is 00h. It can only be written once.
To reset it and allow another write, you must reset the console.
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 56: Pirate SMB3 |
Used only by a pirate copy of Super Mario Bros. 3.
8000h Unknown (always 08h) (maybe counter LSBs, if any) 9000h Bit7-4 of 16bit IRQ counter A000h Bit11-8 of 16bit IRQ counter B000h Bit15-12 of 16bit IRQ counter C000h IRQ Anable (FFh=Enable, 00h=Disable) D000h IRQ Acknowledge (Always write FFh, or EFh) E000h Ignore - MMC3-index (Port 8000h) relicts redirected to E000h F000h Select 8K ROM at 8000h-9FFFh F001h Select 8K ROM at A000h-BFFFh F002h Select 8K ROM at C000h-DFFFh N/A Fixed 8K ROM at E000h-FFFFh (always last bank) F003h Unknown (always 10h) F400h Select 1K VROM at PPU 0000h-03FFh F401h Select 1K VROM at PPU 0400h-07FFh F402h Select 1K VROM at PPU 0800h-0BFFh F403h Select 1K VROM at PPU 0C00h-0FFFh F404h Select 1K VROM at PPU 1000h-13FFh F405h Select 1K VROM at PPU 1400h-17FFh F406h Select 1K VROM at PPU 1800h-1BFFh F407h Select 1K VROM at PPU 1C00h-1FFFh |
The cartridge often uses silly mirrors like C5A7h, mask 8000h-EFFFh by F000h, and F000h-FFFFh by F407h. The IRQ counter is incremented every clock cycle.
| Mapper 57: 6-in-1 |
Used by Game Star 6-in-1 GK-L01A, 6-in-1 GK-L02A, and 54-in-1 GK-54.
8000h Extra Port for CNROM Games in 2nd 64K of VROM
Bit2-0 Select 8K VROM at PPU 0000h-1FFFh (ORed with value in Port 8800h)
Bit5-3 Not used (zero)
Bit6 Must be set for Second 64K Block of VROM
Bit7 Must be set for First 64K Block of VROM
8800h Main Port
Bit2-0 Select 8K VROM at PPU 0000h-1FFFh (ORed with value in Port 8000h)
Bit3 Mirroring (0=Vertical, 1=Horizontal Mirroring)
Bit4 ROM Size (0=16K; Bank X twice, 1=32K; Bank X and X+1)
Bit7-5 Select 16K ROM at 8000h-BFFFh and C000h-FFFFh (X)
|
All carts have 128K ROM and 128K VROM and contain 6 games (even "54-in-1").
| Mapper 58: X-in-1 |
Used by 68-in-1 (a fake containing only 8 games).
C000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A2-A0 Select 16K ROM Bank at 8000h-BFFFh and C000h-FFFFh (X)
A5-A3 Select 8K VROM Bank at PPU 0000h-1FFFh
A6 ROM Size (0=32K; Bank X and X+1, 1=16K; Bank X twice)
A7 Mirroring (0=Vertical, 1=Horizontal Mirroring)
A12-A8 Unknown (Usually 0,/A6,0,/A6,A5,A3, except in yie-ar-kung-fu)
|
Note: Study and Game 32-in-1 declared as "Mapper 58" should be Mapper 241,
Mapper 241: X-in-1 Education
| Mapper 61: 20-in-1 |
Used by 20-in-1.
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A3-0 Select 32K ROM Bank at 8000h-FFFFh
A4 Bank Size (0=32K, 1=16K; only lower/upper half via Bit5)
A5 Select lower/upper half of selected 32K bank (in 16K mode)
A7 Mirroring (0=Vertical, 1=Horizontal Mirroring)
A6,A8-A14 Not used (always 0)
|
There's also a version of the same cartridge with slightly different mapper:
Mapper 231: 20-in-1
| Mapper 62: X-in-1 |
Used by 700-in-1 (a fake containing only somewhat 50-100 games).
8000h-BFFFh Memory Control (Decoded by address AND data lines)
A4-A0,D1-D0 Select 8K VROM at PPU 0000h-1FFFh
A5 ROM Size (0=32K; Bank X-1 and X, 1=16K; Bank X twice)
A7 Mirroring (0=Vertical, 1=Horizontal Mirroring)
A6,A13-A8 Select 16K ROM at 8000h-BFFFh and C000h-FFFFh (X)
A14 Always 0 ?
|
ROM Bank lower bit (A8) should be always SET in 32K Mode. Initially 1st 32K.
| Mapper 64: Tengen RAMBO-1 - PRG/8K, VROM/2K/1K, NT |
This mapper is used on several U.S. unlicensed titles by Tengen. They include
Shinobi, Klax, and Skull & Crossbones.
8000h Index/Control (6bit)
Bit7 CHR Address Select (0=Normal, 1=Address Areas XOR 1000h)
Bit6 PRG Address Select (0=Normal, 1=Address Areas plus 2000h)
Bit3-0 Command Number (Note: Index 0-7 same as for MMC3)
0 - Select 2x1K VROM at PPU 0000h-07FFh (or 1000h-17FFh, if Bit7=1)
1 - Select 2x1K VROM at PPU 0800h-0FFFh (or 1800h-1FFFh, if Bit7=1)
2 - Select 1K VROM at PPU 1000h-13FFh (or 0000h-03FFh, if Bit7=1)
3 - Select 1K VROM at PPU 1400h-17FFh (or 0400h-07FFh, if Bit7=1)
4 - Select 1K VROM at PPU 1800h-1BFFh (or 0800h-0BFFh, if Bit7=1)
5 - Select 1K VROM at PPU 1C00h-1FFFh (or 0C00h-0FFFh, if Bit7=1)
6 - Select 8K ROM at 8000h-9FFFh (or A000h-BFFFh, if Bit6=1)
7 - Select 8K ROM at A000h-BFFFh (or C000h-DFFFh, if Bit6=1)
F - Select 8K ROM at C000h-DFFFh (or 8000h-9FFFh, if Bit6=1)
N/A - Fixed 8K ROM at E000h-FFFFh (always last 8K bank)
8 - Select 1K VROM page at PPU 0400h
9 - Select 1K VROM page at PPU 0C00h
8001h Data Register (indexed via Port 8000h)
A000h ?Mirroring Select (Bit0: 0=Horizontal, 1=Vertical Mirroring)
No confidence in the accuracy of this information.
|
At reset, all four 8K banks are set to the last 8K bank in the cart.
Carts with VROM initially map the first 8K of VROM to PPU 0000h-1FFFh on
reset. Carts without VROM should always have 8K of VRAM at PPU 0000h-1FFFh.
| Mapper 65: Irem H-3001 - PRG/8K, VROM/1K, NT, IRQ |
Used by Daiku no Gensan 2, Kaiketsu Yanchamaru 3, and Spartan X 2.
Note: Ai Sensei no Oshiete declared as "Mapper 65" is maybe a Konami mapper?
9000h Unknown 9001h Unknown 9003h,9004h IRQ Control (not sure about difference between 9003h/9004h) (00h=Disable IRQ, C0h=Enable IRQ, other values unknown) 9005h IRQ Counter MSB of decrementing 16bit counter 9006h IRQ Counter LSB of decrementing 16bit counter B000h Select 1K VROM bank at PPU 0000h-03FFh B001h Select 1K VROM bank at PPU 0400h-07FFh B002h Select 1K VROM bank at PPU 0800h-0BFFh B003h Select 1K VROM bank at PPU 0C00h-0FFFh B004h Select 1K VROM bank at PPU 1000h-13FFh B005h Select 1K VROM bank at PPU 1400h-17FFh B006h Select 1K VROM bank at PPU 1800h-1BFFh B007h Select 1K VROM bank at PPU 1C00h-1FFFh 8000h Select 8K ROM bank at 8000h-9FFFh (initially 1st half of 1st 16K) A000h Select 8K ROM bank at A000h-BFFFh (initially 2nd half of 1st 16K) C000h Select 8K ROM bank at C000h-DFFFh (initially 1st half of last 16K) N/A Fixed 8K ROM bank at E000h-FFFFh (always 2nd half of last 16K) |
| Mapper 66: GNROM - PRG/32K, VROM/8K |
This mapper is used on several Japanese titles, such as Dragon Ball, and on
U.S. titles such as Gumshoe and Dragon Power.
8000h-FFFFh Memory Control (2x2bits)
Bit1-0 Select 8K VROM bank at PPU 0000h-1FFFh (initially 1st bank)
Bit5-4 Select 32K ROM bank at 8000h-FFFFh (initially 1st bank)
|
This mapper is used on the DragonBall (NOT DragonBallZ) NES game.
| Mapper 67: Sunsoft3 - PRG/16K, VROM/2K, IRQ |
Used by Fantasy Zone 2.
8000h IRQ Acknowledge (write any data to this address)
8800h-8FFFh Select 2K VROM bank at PPU 0000h-07FFh
9800h-9FFFh Select 2K VROM bank at PPU 0800h-0FFFh
A800h-AFFFh Select 2K VROM bank at PPU 1000h-17FFh
B800h-BFFFh Select 2K VROM bank at PPU 1800h-1FFFh
C800h-CFFFh IRQ Counter (two writes: 1st=MSB, 2nd=LSB)
(16bit decrementing clock cycle counter)
D800h-DFFFh IRQ Control (Bit4: 0=Disable, 1=Enable)
E800h-EFFFh No info - maybe Mirroring control ?
F800h-FFFFh Select 16K ROM bank at 8000h-BFFFh (initially 1st bank)
N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank)
|
| Mapper 68: Sunsoft4 - PRG/16K, VROM/2K, NT-VROM |
This mapper is used by After Burner I and II, and by Maharaja.
8000h Select 2K VROM bank at PPU 0000h-07FFh
9000h Select 2K VROM bank at PPU 0800h-0FFFh
A000h Select 2K VROM bank at PPU 1000h-17FFh
B000h Select 2K VROM bank at PPU 1800h-1FFFh
C000h Select 1K VROM bank as BLK0 (in VROM Mode) (from LAST 128 banks)
D000h Select 1K VROM bank as BLK1 (in VROM Mode) (from LAST 128 banks)
E000h Name Table Control
Bit4 Name Table VROM Mode (0=VRAM, 1=VROM via Port C000h/D000h)
Bit0 Name Table Mirroring (0=Horizontal, 1=Vertical Mirroring)
F000h Select 16K ROM bank at 8000h-BFFFh (initially 1st bank)
N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank)
|
| Mapper 69: Sunsoft5 FME-7 - PRG/8K, VROM/1K, NT ctrl, SRAM, IRQ |
This mapper is used by Batman, Hebereke, Pyokotan no Da Meiro, Barcode World,
Gremlin 2, Honoo no Doukyuuji 1 and 2, and Gimmick.
8000h Index Register (4bit)
0 - Select 1K VROM at PPU 0000h-03FFh
1 - Select 1K VROM at PPU 0400h-07FFh
2 - Select 1K VROM at PPU 0800h-0BFFh
3 - Select 1K VROM at PPU 0C00h-0FFFh
4 - Select 1K VROM at PPU 1000h-13FFh
5 - Select 1K VROM at PPU 1400h-17FFh
6 - Select 1K VROM at PPU 1800h-1BFFh
7 - Select 1K VROM at PPU 1C00h-1FFFh
8 - Select 8K ROM/RAM at 6000h-7FFFh
Bit6=0 --> Select 8K ROM (Page number in bit5-0)
Bit6=1,Bit7=1 --> Select 8K SRAM
Bit6=1,Bit7=0 --> Select 8K "pseudo-random numbers?"
9 - Select 8K ROM at 8000h-9FFFh
A - Select 8K ROM at A000h-BFFFh
B - Select 8K ROM at C000h-DFFFh
C - Select Mirroring
0 Two-Screen, Vertical Mirroring
1 Two-Screen, Horizontal Mirroring
2 One-Screen, BLK0
3 One-Screen, BLK1
D - IRQ control (00h=Disable, 81h=Enable, other values?)
E - IRQ LSB of decrementing clock cycle counter
F - IRQ MSB of decrementing clock cycle counter
N/A - Fixed 8K ROM at E000h-FFFFh (always last 8K bank)
A000h Data Register (indexed via Port 8000h)
|
| Mapper 70: Bandai - PRG/16K, VROM/8K, NT |
Used by Taito's Arkanoid 2, and various Bandai games: Space Shadow, Kamen
Rider Club, Saint Seiya, Pocket Zaurus, Gegege no Kitarou 2, and two Family
Trainer games.
C000h-C0FFh Memory Control Bit7 Name Table Select (0/1 = BLK0/BLK1) (One-Screen Mode only) Bit6-4 Select 16K ROM at 8000h-BFFFh Bit3-0 Select 8K VROM at PPU 0000h-1FFFh |
Bus-Conflicts, memory at C000h-C0FFh should be filled by 00h-FFh.
| Mapper 71: Camerica - PRG/16K |
This mapper is used on Camerica's unlicensed NES carts, including Firehawk
and Linus Spacehead.
8000h-BFFFh Unknown C000h-FFFFh Select 16K ROM bank at 8000h-BFFFh (initially 1st bank) N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank) |
All carts using it have 8K of VRAM at PPU $0000.
Many ROMs from these games are incorrectly defined as mapper 2.
| Mapper 72: Jaleco Early Mapper 0 - PRG-LO, VROM/8K |
Used by Pinball Quest, Pro Tennis, Pro Judo.
8000h-FFFFh Memory Control
Bit7-6 Function Select
0 Confirm Selection
1 Select 8K VROM bank at PPU 0000h-1FFFh
2 Select 16K ROM bank at 8000h-BFFFh (lower half of PRG memory)
3 Reserved (would probably select both PRG+VROM)
Bit5-4 Not used
Bit0-3 ROM or VROM Bank Number for above Selection
|
Bus-conflicts. Example: To select PRG Bank 7, first write 87h, then 07h.
Same as Mapper 92, except that this one maps the LOWER half of PRG memory.
Not sure if that makes sense, but it appears to consist of three latches,
latch1 directly accessed from CPU, the other latches loaded from the latch1
on high-to-low transitions in bit6/7.
| Mapper 73: Konami VRC3 - PRG/16K, IRQ |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 74: Whatever MMC3-style |
Reportedly "Taiwan MMC3 -Varient Mapper#0" used by "KidNiKi3J(hacked)".
Personally, I have a ROM-image named "Ji Jia Zhan Shi", which may or may not
be same as "KidNiKi3J(hacked)".
Anyways, that ROM-image seems to be basically MMC3-compatible,
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
except that it gets wrong anytime when selecting ROM bank number 14h via
Register 7, don't know what is/should be happenening there (?)
| Mapper 75: Jaleco SS8805/Konami VRC1 - PRG/8K, VROM/4K |
Mapper 21-26,73,75,85: Konami VRC Mappers
| Mapper 76: Namco 109 - PRG/8K, VROM/2K |
Used by Digital Devil / Megami Tensei.
8000h Index/Control (3bit)
Bit2-0 Command Number
0 - Not used
1 - Not used
2 - Select 2K VROM at PPU 0000h-07FFh
3 - Select 2K VROM at PPU 0800h-0FFFh
4 - Select 2K VROM at PPU 1000h-17FFh
5 - Select 2K VROM at PPU 1800h-1FFFh
6 - Select 8K ROM at 8000h-9FFFh
7 - Select 8K ROM at A000h-BFFFh
N/A - Fixed 16K ROM at C000h-FFFFh (always last bank)
8001h Data Register (Indexed via Port 8000h)
|
| Mapper 77: Irem - PRG/32K, VROM/2K, VRAM 6K+2K |
Used by Napoleon Senki.
8000h-FFFFh Memory Control
Bit0-1 Select 32K ROM bank at 8000h-FFFFh
Bit2-3 Not used
Bit4-7 Select 2K VROM bank at PPU 0000h-07FFh
6K VRAM at PPU 0800h-1FFFh (ie. upper 6K of Pattern Tables are VRAM)
2K VRAM at PPU 2800h-2FFFh (ie. uses Four-Screen Name Tables)
|
Bus-conflicts.
| Mapper 78: Irem 74HC161/32 - PRG/16K, VROM/8K |
Used by Holy Diver, and Cosmo Carrier (Uchuusen). The two games seem to be
using different/incompatible mapper circuits for name table control?
8000h-FFFFh Memory Control
Bit2-0 Select 16K ROM bank at 8000h-BFFFh (initially 1st bank)
N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank)
Bit3 Name Table Control
Jaleco/Cosmo Carrier: One-Screen (0=BLK0, 1=BLK1)
Irem/Holy Diver: Two-Screen (0=Horizontal, 1=Vertical Mirroring)
Bit7-4 Select 8K VROM bank at PPU 0000h-1FFFh
|
| Mapper 79: AVE Nina-3 - VROM/8K |
[See also]
Mapper 113: Sachen/Hacker/Nina
Made by American Video Entertainment (AVE), used by Krazy Kreatures, Double
Strike, etc.
4100h Bit1-0 Select 8K VROM bank at PPU 0000h-1FFFh |
Port decoded as A14=A8=HIGH, A15=A13=LOW, ie. with mirrors at 4100h-41FFh, 4300h-43FFh ... 5F00h-5FFFh. Contains 74LS175, 74LS138, and "Nina"-lockout chip.
| Mapper 80: Taito X-005 - PRG/8K, VROM/2K/1K, NT |
Used by Fudou Myouou Den (Demon Sword), Kyonshiizu 2, Mirai Shinwa Jarvas,
Taito Grand Prix - Eikou heno License, Yamamura Misa Suspense - Kyouto Ryuu
no Tera Satsujin, Minelvaton Saga.
7EF0h Select 2x1K VROM at PPU 0000h-07FFh (Bit7: Name Table, see below) 7EF1h Select 2x1K VROM at PPU 0800h-0FFFh (Bit7: Name Table, see below) 7EF2h Select 1K VROM at PPU 1000h-13FFh 7EF3h Select 1K VROM at PPU 1400h-17FFh 7EF4h Select 1K VROM at PPU 1800h-1BFFh 7EF5h Select 1K VROM at PPU 1C00h-1FFFh 7EF6h Unknown (usually FFh, 01h, or 00h) 7EF8h SRAM Enable (A3h=Enable, FFh=Disable) 7EFAh Select 8K ROM 8000h-9FFFh 7EFCh Select 8K ROM A000h-BFFFh 7EFEh Select 8K ROM C000h-DFFFh N/A Fixed 8K ROM E000h-FFFFh (always last bank) 7EF7h,7EF9h Not used 7EFBh,7EFDh,7EFFh Dupes of 7EFAh,7EFCh,7EFEh used by Kyonshiizu 2 only 7F00h-7FFFh SRAM Area (seems to be only 256 bytes or less used) |
Bit7 of 7EF0h and Bit7 of 7EF1h are somehow related to Name Tables: Most carts use Vertical Mirroring, these carts always have both bits cleared. Demon Sword uses One-Screen mode, either both bits cleared (BLK0), or both bits set (BLK1).
| Mapper 81: AVE Nina-6 |
Made by American Video Entertainment (AVE), used by Deathbots, Mermaids of
Atlantis, etc.
No info. For Deathbots, see:
Mapper 113: Sachen/Hacker/Nina
Also, presumably mis-numbered "Mapper 81 - Taito C075"
Reportedly "Tatio C075" used by "(many Japanese title from tatio)".
Don't have a ROM-image that is assigned as Mapper 81. Don't know which titles
are using it. Maybe meant to be Taito's Arkanoid 2, ie. this mapper:
Mapper 70: Bandai - PRG/16K, VROM/8K, NT
| Mapper 82: Taito X1-17 - PRG/8K, VROM/2K/1K |
Used by SD Keiji Blader, and Kyuukyoku Harikiri 1, 2, 3.
7EF0h Select 2x1K VROM at PPU 0000h-07FFh (or 1000h-17FFh if swapped) 7EF1h Select 2x1K VROM at PPU 0800h-0FFFh (or 1800h-1FFFh if swapped) 7EF2h Select 1K VROM at PPU 1000h-13FFh (or 0000h-03FFh if swapped) 7EF3h Select 1K VROM at PPU 1400h-17FFh (or 0400h-07FFh if swapped) 7EF4h Select 1K VROM at PPU 1800h-1BFFh (or 0800h-0BFFh if swapped) 7EF5h Select 1K VROM at PPU 1C00h-1FFFh (or 0C00h-0FFFh if swapped) 7EF6h Swap PPU 0000h-0FFFh / 1000h-1FFFh (Bit1: 0=Normal, 1=Swap) 7EF7h SRAM .... CAh,00h,01h,40h 7EF8h SRAM .... 69h,00h,40h 7EF9h SRAM .... 84h,00h,40h 7EFAh Select 8K ROM 8000h-9FFFh (Bit7-2) 7EFBh Select 8K ROM A000h-BFFFh (Bit7-2) 7EFCh Select 8K ROM C000h-DFFFh (Bit7-2) N/A Fixed 8K ROM E000h-FFFFh (unknown?) 7EFDh SRAM .... FFh 7EFEh SRAM .... FFh,07h 7EFFh SRAM .... FFh 6000h-7FFFh SRAM Area (probably 8K size, at least 6000h-73xxh used) |
| Mapper 83: Cony |
There are different Cony variants for cartridges of different size:
Cony (A) 128K+256K Fatal Fury 2 Cony (B) 256K+512K World Heroes 2 Cony (C) 4x256K+4x256K Dragon Ball Z 4-in-1 Also used by Garou Densetsu Special? |
Cony (A) and (C) only - 8bit bank numbers (256x1K=256K):
8310h Select 1K VROM at PPU 0000h-03FFh (in current 256K block) 8311h Select 1K VROM at PPU 0400h-07FFh (in current 256K block) 8312h Select 1K VROM at PPU 0800h-0BFFh (in current 256K block) 8313h Select 1K VROM at PPU 0C00h-0FFFh (in current 256K block) 8314h Select 1K VROM at PPU 1000h-13FFh (in current 256K block) 8315h Select 1K VROM at PPU 1400h-17FFh (in current 256K block) 8316h Select 1K VROM at PPU 1800h-1BFFh (in current 256K block) 8317h Select 1K VROM at PPU 1C00h-1FFFh (in current 256K block) |
Cony (B) only - 8bit bank numbers (256x2K=512K):
8310h Select 2K VROM at PPU 0000h-07FFh 8311h Select 2K VROM at PPU 0800h-0FFFh 8316h Select 2K VROM at PPU 1000h-17FFh 8317h Select 2K VROM at PPU 1800h-1FFFh |
Cony (A) only - 4bit bank numbers (16x8K=128K):
8300h Select 8K ROM at 8000h-9FFFh 8301h Select 8K ROM at A000h-BFFFh 8302h Select 8K ROM at C000h-DFFFh N/A Fixed 8K ROM at E000h-FFFFh (always last bank) |
Cony (B) and (C) only - 4bit bank numbers (16x16K=256K):
8000h Select 16K ROM at 8000h-BFFFh (in current 256K block) N/A Fixed 16K ROM at C000h-FFFFh (last bank in current 256K block) |
Cony (A) and (B) and (C):
8200h IRQ Counter LSB, writing to this address acknowledges IRQs 8201h IRQ Counter MSB, writing to this address starts counting |
Cony (A) and (B) only:
8100h IRQ Control (Bit7=Enable IRQs) (other bits unknown) Bit7, unlike C 5000h Unknown, program reads from this address |
Cony (C) only:
8100h IRQ Control (Bit1=Enable IRQs) (other bits unknown) Bit1, unlike A/B
B000h Select 256K ROM/VROM Windows (upper two address bits)
Bit0-3 Unknown
Bit4,6 Bit0 of 256K Block Number
Bit5,7 Bit1 of 256K Block Number
Used values are 00h,50h,A0h,F0h. Other values could probably select
separate 256K banks for ROM/VROM. The ROM selection also affects
the "fixed" 16K at C000h-FFFFh (last bank in current 256K block).
B0FFh Probably same as B000h
B1FFh Probably same as B000h
510Xh Unknown, program reads/writes to/from this address
430Xh Unknown, program reads from this address
|
| Mapper 84: Whatever |
No info. Reportedly "PC-SMB2J" used by "SMBJ2".
Don't have a ROM-image, unless it is meant to be same as Mapper 40 or 50:
Mapper 40: FDS-Port - Lost Levels
Mapper 50: FDS-Port - Alt. Levels
| Mapper 85: Konami VRC7A/B - PRG/16K/8K, VROM/1K, NT, IRQ, SOUND |
VRC7 General Memory and IRQ Registers
Mapper 21-26,73,75,85: Konami VRC Mappers
VRC7 Sound Registers
The sound generation is done using FM synthesis, so the music sounds like
"Adlib" OPL2 music. All sound registers are accessed through only two
physical registers.
9010h (aka 9.1.0) Index register 9030h (aka 9.1.1) Data Register |
There are 6 channels, each containing three registers, and 8 custom instrument control registers.
Index 10h-15h - Channel 0-5, Frequency LSB
Bit7-0 Lower 8bit of 9bit Frequency (f; 0-1FFh) |
Index 20h-25h - Channel 0-5, Frequency MSB, Octave, Trigger
Bit7-5 Unknown Bit4 Channel trigger Bit3-1 Octave Select (o; 0-7) Bit0 Upper 1bit of 9bit Frequency (f; 0-1FFh) |
Frequency is calculated as: F = 49722Hz * f / 2^(19-o)
Index 30h-35h - Channel 0-5, Instrument and Volume
Bit7-4 Instrument number (0=Custom, 1-0Fh=Fixed Instruments) Bit3-0 Volume |
Index 00h-07h - Custom Instrument (Instrument 0)
Note: I will not provide too extensive documentation of the instrument
registers since their functions are identical to those of the OPL2 chip,
commonly found on Adlib/Soundblaster/compatible cards, and there is alot
of information out on how to program these. I will use terminology
similar to that found in said documents. My VRC7 "emulator" test program
I wrote simply re-arranged and tweaked the register writes to correspond
with the OPL2 registers.
Here's a link to a good document about this chip: http://www.ccms.net/~aomit/oplx/ |
The tremolo depth is set to 4.3db and the vibrato depth is set to 14 cent
(in reguards to OPL2 settings; to achieve this you would write 0C0h to
OPL register 0BDh). All operator connections are fixed in FM mode. (Where
Modulator modulates the Carrier).
Index 00h (Modulator)
Index 01h (Carrier)
Bit7 Tremolo Enable Bit6 Vibrato Enable Bit5 Sustain Enable Bit4 KSR Bit3-0 Multiplier |
Index 02h
Bit7-6 Key Scale Level Bit5-0 Output Level |
Index 03h
Bit7-5 Not used (Write 0's)
Bit4 Carrier Waveform
Bit3 Modulator Waveform
There are only two waveforms available. Sine and rectified sine (only
the positive cycle of the sine; negative cycle "chopped off".)
Bit2-0 Feedback Control
|
Index 04h (Modulator)
Index 05h (Carrier)
Bit7-4 Attack Bit3-0 Decay |
Index 06h (Modulator)
Index 07h (Carrier)
Bit7-4 Sustain Bit3-0 Release |
Register Settings for the 15 fixed instruments
These instruments are not 100% correct! There is no way to extract the
register settings from the chip short of an electron microscope.
I have "tuned" these instruments best I could, though I know a couple
are not exactly right.
Table shows Register 0-7 settings for Instrument 1-0Fh
1 - 05 03 10 06 74 A1 13 F4 2 - 05 01 16 00 F9 A2 15 F5 3 - 01 41 11 00 A0 A0 83 95 4 - 01 41 17 00 60 F0 83 95 5 - 24 41 1F 00 50 B0 94 94 6 - 05 01 0B 04 65 A0 54 95 7 - 11 41 0E 04 70 C7 13 10 8 - 02 44 16 06 E0 E0 31 35 9 - 48 22 22 07 50 A1 A5 F4 A - 05 A1 18 00 A2 A2 F5 F5 B - 07 81 2B 05 A5 A5 03 03 C - 01 41 08 08 A0 A0 83 95 D - 21 61 12 00 93 92 74 75 E - 21 62 21 00 84 85 34 15 F - 21 62 0E 00 A1 A0 34 15 |
| Mapper 86: Jaleco Early Mapper 2 - PRG/32K, VROM/8K |
Used only by Moero Pro Baseball (Red/Black).
6000h Memory Control
Bit6,1,0 Select 8K VROM bank at PPU 0000h-1FFFh
Bit5,4 Select 32K ROM bank at 8000h-FFFFh
Bit7,3,2 Not used (always zero)
7000h Unknown
|
Also used by Lum no Wedding Bell though that does use only VROM banking.
Functional same as Mapper 87, though that does as well use only VROM banking.
| Mapper 87: Jaleco/Konami 16K VROM - VROM/8K |
Used only by Hyper Olympic, Goonies, Choplifter, Argus, Ninja Jajamaru Kun,
City Connection.
6000h Select 8K VROM bank at PPU 0000h-1FFFh (Bit 1 used only) |
| Mapper 88: Namco 118 |
Used by Devil Man, Dragon Spirit, Namcot Mahjong 3, Quinty.
8000h Index/Control (3bit)
Bit2-0 Command Number
0 - Select 2x1K VROM at PPU 0000h-07FFh (Banks 0-63)
1 - Select 2x1K VROM at PPU 0800h-0FFFh (Banks 0-63)
2 - Select 1K VROM at PPU 1000h-13FFh (Banks 64-127)
3 - Select 1K VROM at PPU 1400h-17FFh (Banks 64-127)
4 - Select 1K VROM at PPU 1800h-1BFFh (Banks 64-127)
5 - Select 1K VROM at PPU 1C00h-1FFFh (Banks 64-127)
6 - Select 8K ROM at 8000h-9FFFh
7 - Select 8K ROM at A000h-BFFFh
N/A - Fixed 16K ROM at C000h-FFFFh (always last bank)
8001h Data Register (Indexed via Port 8000h)
|
The carts have 128K VROM, of which the lower 64K can be mapped only to Pattern Table 0, the upper 64K only to Pattern Table 1.
Devil Man additionally writes 00h to Port C000h, purpose unknown.
Devil Man ROM-image is declared as 4-screen-vertical-mirror, that is nonsense.
| Mapper 89: Sunsoft Early - PRG/16K, VROM/8K |
Used by only by Mito Koumon.
8000h-FFFFh Memory Control
Bit7 Unknown - maybe Name Table related, maybe not.
Bit6-4 Select 16K ROM bank at 8000h-BFFFh
N/A Fixed 16K ROM bank at C000h-FFFFh (always last bank)
Bit3-0 Select 8K VROM bank at PPU 0000h-1FFFh
|
The program seems to attempt to (unsuccesfully) resolve bus-conflicts.
| Mapper 90: Pirate MMC5-style |
Used by some pirate titles (Taiwan) such as Super Mario World, Tekken2 and
Mortal Kombat. Features similar functions as MMC5, though the Port addresses
are completely different.
5000h(W) Maths Coprocessor Parameter A 5001h(W) Maths Coprocessor Parameter B 5000h(R) Maths Coprocessor 8bit Result of A*B 8000h PRG 8K at 8000h-9FFFh 8001h PRG 8K at A000h-BFFFh or 16k PRG bank at $A000-? 8002h PRG 8K at C000h-DFFFh 8003h PRG 8K at E000h-FFFFh 9000h/A000h LSB/MSB of VROM bank at PPU 0000h (1K,2K,4K,8K) 9001h/A001h LSB/MSB of VROM bank at PPU 0400h (1K) 9002h/A002h LSB/MSB of VROM bank at PPU 0800h (1K,2K) 9003h/A003h LSB/MSB of VROM bank at PPU 0C00h (1K) 9004h/A004h LSB/MSB of VROM bank at PPU 1000h (1K,2K,4K) 9005h/A005h LSB/MSB of VROM bank at PPU 1400h (1K) 9006h/A006h LSB/MSB of VROM bank at PPU 1800h (1K,2K) 9007h/A007h LSB/MSB of VROM bank at PPU 1C00h (1K) B000h/B004h LSB/MSB of 1K VROM bank at PPU 2000h (Name Table VROM mode) B001h/B005h LSB/MSB of 1K VROM bank at PPU 2400h (Name Table VROM mode) B002h/B006h LSB/MSB of 1K VROM bank at PPU 2800h (Name Table VROM mode) B003h/B007h LSB/MSB of 1K VROM bank at PPU 2C00h (Name Table VROM mode) |
$C000 irq registers Unknown
$C001 irq registers Unknown
$C006 irq registers Unknown
$C007 irq registers Unknown
$C002 irq clear irq_flag=0 and INT signal is clear
$C003 irq reset if $C005=0, irq_flag=0
else, irq_flag=1 and irq_counter=irq_latch
$C004 irq reset It seems same of $C003
$C005 irq counter irq_flag=1, irq_latch = irq_counter = value
|
IRQs work like MMC3 does.
IRQ counter is decremented at every scanline, always while not blanking
(scanline < 240), and background or sprites are enabled. When it reaches
zero (or a negative value), IRQ is triggered _IF_ the irq_flag is set,
clearing the irq_flag and irq_latch.
D000h Bank Mode
Bit1-0 PRG Bank Size
0 Fixed last 32K at 8000h-FFFFh (initial setting)
1 16K Banks, and Fixed last 16K at C000h-FFFFh
2 8K Banks, via Bits 2,7, and Ports 8000h-8003h
3 8K in reverse mode?
Bit2 PRG Bank at E000h in 8K Mode (0=Last 8K, 1=Port 8003h)
Bit4-3 VROM Bank Size (0=8K, 1=4K, 2=2K, 3=1K)
Bit5 Name Table Source (0=VRAM via D001h, 1=VROM via B00Xh)
Bit6 Not used
Bit7 PRG Bank at 6000h (1=enabled) (Similiar/Instead E000h?)
D001h Name Table Control (in VRAM mode) (only lower 2bit used)
0 Two-Screen, Vertical mirroring
1 Two-Screen, Horizontal mirroring
2,3 One-Screen, BLK0
|
$D002 unknown Unused? $D003 bank page Only used by larger carts |
if (bankmode.bit5), map CHR data in the nametable area using $B00x values,
But, if (high byte, low byte) != (0,0) or (0,1) or (0,2) or (0,3),
so bankmode.bit5 is cleared, and mirroring does not change.
for(i=0;i<4;i++) {
if(!nam_high_byte[i] && (nam_low_byte[i] == i)) {
bankmode &= 0xdf; //clear bit5 --> use VRAM with mirroring
return;
next
|
If you ignore it, a lot of crappy gfx might be displayed.
| Mapper 91: HK-SF3 - PRG/8K, VROM/2K, IRQ |
This mapper is used on the pirate cart with a title screen reading "Street
Fighter 3". It may or may not have been used in other bootleg games.
6000h Select 2K VROM bank at PPU 0000h-07FFh 6001h Select 2K VROM bank at PPU 0800h-0FFFh 6002h Select 2K VROM bank at PPU 1000h-17FFh 6003h Select 2K VROM bank at PPU 1800h-1FFFh 7000h Select 8K ROM bank at 8000h-9FFFh 7001h Select 8K ROM bank at A000h-BFFFh N/A Fixed 16K ROM bank at C000h-FFFFh (always last 16K) 7006h IRQ Disable/Acknowledge (write any value) 7007h IRQ Enable (write any value) |
When enabled, IRQs are requested every 8 scanlines, except during VBlank.
Vertical mirroring is always active.
| Mapper 92: Jaleco Early Mapper 1 - PRG-HI, VROM/8K |
Used by Moero Pro Soccer, Moero Pro Baseball'88.
8000h-FFFFh Memory Control
Bit7-6 Function Select
0 Confirm Selection
1 Select 8K VROM bank at PPU 0000h-1FFFh
2 Select 16K ROM bank at C000h-FFFFh (upper half of PRG memory)
3 Reserved (would probably select both PRG+VROM)
Bit5-4 Not used
Bit0-3 ROM or VROM Bank Number for above Selection
|
Bus-conflicts. Example: To select PRG Bank 7, first write 87h, then 07h.
Same as Mapper 72, except that this one maps the UPPER half of PRG memory.
| Mapper 93: 74161/32 - PRG/16K |
Used only by Fantasy Zone.
8000h-FFFFh Memory Control
Bit0 Unknown, seems to be always set.
Bit1-3 Always zero
Bit4-6 Select 16K ROM bank at 8000h-BFFFh
Bit7 Always zero
|
Bus-conflicts. Uses VRAM.
| Mapper 94: 74161/32 - PRG/16K |
Used only by Senjou no Okami (Capcom's Commando, japanese version).
8000h-FFFFh Memory Control
Bit0-1 Always zero
Bit2-4 Select 16K ROM bank at 8000h-BFFFh
Bit5-7 Always zero
|
Bus-conflicts. Uses VRAM.
| Mapper 95: Namcot MMC3-Style |
Looks like MMC3, but doesn't seem to have IRQs and various other functions.
Used by Dragon Buster 1, and maybe many other "MMC3" games.
8000h Index/Control (3bit)
Bit2-0 Command Number
0 - Select 2x1K VROM at PPU 0000h-07FFh
1 - Select 2x1K VROM at PPU 0800h-0FFFh
2 - Select 1K VROM at PPU 1000h-13FFh
3 - Select 1K VROM at PPU 1400h-17FFh
4 - Select 1K VROM at PPU 1800h-1BFFh
5 - Select 1K VROM at PPU 1C00h-1FFFh
6 - Select 8K ROM at 8000h-9FFFh
7 - Select 8K ROM at A000h-BFFFh
N/A - Fixed 16K ROM at C000h-FFFFh (always last bank)
8001h Data Register (Indexed via Port 8000h)
|
| Mapper 96: 74161/32 |
Used by Oeka Kids - Anpanman no Hiragana Daisuki, Anpanman to Oekaki Shiyou.
(These games seem to require a special controller ?)
8000h-FFFFh Bit0-1 Select 32K ROM bank at 8000h-FFFFh (2bit) Bit2 Unknown (maybe MSB of above for bigger ROMs) |
Bus-conflicts. Same as AOROM, but without BLK0/BLK1 select. Has VRAM.
| Mapper 97: Irem - PRG HI |
Used by Kaiketsu Yanchamaru.
8000h-FFFFh Memory Control
Bit7-6 Unknown (used values are 1,2 - values 0,3 unused)
(Maybe Name Table Mirroring)
Bit5-4 Not used (always zero)
Bit3-0 Select 16K ROM bank at C000h-FFFFh (upper block!)
N/A Fixed 16K ROM bank at 8000h-BFFFh (always LAST 16K bank)
|
Bus-conflicts.
| Mapper 99: VS Unisystem Port 4016h - VROM/8K |
Used by VS Super Mario Bros, VS Ice Climber, VS Excitebike and others.
Port 4016h/Write: Bit2 Select 8K VROM bank at PPU 0000h-1FFFh (VS Unisystem only) Bit0 Joypad Strobe |
Most of these games use 4-screen mirroring. Above bank selection uses an expansion port output, which does not show up on NES/Famicom cartridge bus, and thus works only with VS Unisystem arcade machines. The machine also includes special DIP-Switch and Credit I/O ports as described in Controllers chapter.
| Mapper 100: Whatever |
No info. Don't have any such ROM-images.
Reportedly "MMC3/Nestice/Trainer/Buugy Mode Used in hacked roms !!"
Sounds like homebrew hacks that work only on certain emulators, but not on
real MMC3 hardware. Or it is just meant to be corrupted .NES files with
garbage in reserved header entries at [07h..0Fh].
| Mapper 105: X-in-1 MMC1 |
Used by Nintendo World Championships 1990. Works similar like normal MMC1:
Mapper 1: MMC1 - PRG/32K/16K, VROM/8K/4K, NT
However, the four registers are used like this:
Register 0 Configuration Register (same as MMC1) Register 1 ROM Bank Base (Bit4 unknown) Register 2 Not used Register 3 ROM Bank (same as MMC1, but ORed with Base) |
And, accessing Register 3 via Port FFF0h (instead normal FFFFh) appears to mask (zero) the new Register 3 bank number, until writing to Register 1.
Initially first 32K.
NB. The Championships 3-in-1 multicart doesn't have a game selection menu, it
runs game 1 until reaching a certain score, and then switches to game 2, and
so on. The controls are strange: it appears one can start the cartridge only
when connecting a zapper to port 1, or a joypad to port 2, whilst gameplay
works only with joypad at port 1.
| Mapper 112: Asder - PRG/8K, VROM/2K/1K |
Used by Huang Di, and San Guo Zhi - Qun Xiong Zheng Ba.
8000h Index (0-7)
0 Select 8K ROM at 8000h-9FFFh
1 Select 8K ROM at A000h-BFFFh
2 Select 2x1K VROM at PPU 0000h-07FFh
3 Select 2x1K VROM at PPU 0800h-0FFFh
4 Select 1K VROM at PPU 1000h-13FFh
5 Select 1K VROM at PPU 1400h-17FFh
6 Select 1K VROM at PPU 1800h-1BFFh
7 Select 1K VROM at PPU 1C00h-1FFFh
N/A Fixed 16K ROM at C000h-FFFFh (always last 16K)
A000h Data (indexed via Port 8000h)
C000h Unknown, always 00h
E000h Unknown, always 00h
|
| Mapper 113: Sachen/Hacker/Nina |
[Seems to be same as Nina-3 and/or Nina-6]
Mapper 79: AVE Nina-3 - VROM/8K
Mapper 81: AVE Nina-6
Used by Metal Fighter, Side Winder, Rad Racket - Deluxe Tennis II, AV
Hanafadu Club, AV Soccer, Papillion, Deathbots, Mahjong Companion, 4-in-1
Total Funpack.
4100h-41FFh Memory Control (commonly used addresses: 4100h, 4101h, 4120h)
Bit0-2 Select 8K VROM bank at PPU 0000h-1FFFh
Bit3-4 Select 32K ROM bank at 8000h-FFFFh (bigger carts only)
|
Many of these games seem to have been originally desiged for mappers at 8000h-FFFFh, and do still write to these addresses. Also, "16 Mahjong" is declared as Mapper 113, though it uses 8000h-FFFFh only?
There's also a variant in which ROM selection is moved to Bit2:
Mapper 133: Sachen
| Mapper 114: Super Games |
Used by Lion King, Super Donkey Kong, and Pocohontos. Mask addresses by E001h.
6000h Unknown (usually zero, except Lion King before crashing?) 8000h Unknown (see notes below) A000h Memory Control Index (see list below) C000h Memory Control Data (indexed via A000h) E000h IRQ Acknowledge (write any value) 6001h Unknown (always zero) 8001h Unknown (see notes below) A001h IRQ Counter (MMC3-style, decremented per scanline, paused in VBlank) C001h IRQ Counter E001h IRQ Start |
Memory Control Indexes are:
0 Select 2x1K VROM at PPU 0000h-07FFh 1 Select 1K VROM at PPU 1400h-17FFh 2 Select 2x1K VROM at PPU 0800h-0FFFh 3 Select 1K VROM at PPU 1C00h-1FFFh 4 Select 8K ROM at 8000h-9FFFh 5 Select 8K ROM at A000h-BFFFh 6 Select 1K VROM at PPU 1000h-13FFh 7 Select 1K VROM at PPU 1800h-1BFFh |
Port 8001h, Bit0 seems to be used as IRQ disable in Lion King. All games seem to use Vertical Mirroring, but Pocohontos seems to toggle Name Tables via Port 8000h and 8001h during initialization.
| Mapper 115: MMC3 Cart Saint |
Used by Yuu Yuu Hakusho Final - Makai Saikyou Retsuden.
6000h Unknown (used values 00h, A0h, A4h) 6001h Unknown (always 00h) |
No idea how it does <really> work, but the game appears to work when selecting 8K ROM bank number 8 at 8000h-9FFFh when [6000h]=A4h. Otherwise the mapper works like MMC3:
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
Note: MMC3 Register 7 <must> be initialized to 01h on reset.
| Mapper 116: Whatever |
No info. Don't have a ROM-image.
Reportedly "PC-Reserved" used by "AV beautiy fighting(not playable yet)".
| Mapper 117: Future |
Used by Sangokushi 4 (a clone of Warrior of Fate).
Appears related with Mapper 90.
8000h Select 8K ROM at 8000h-9FFFh 8001h Select 8K ROM at A000h-BFFFh 8002h Select 8K ROM at C000h-DFFFh N/A Fixed 8K ROM at E000h-FFFFh (last bank) 9000h Unknown (always FFh) 9001h Unknown (always 08h) 9003h Unknown (always 00h) A000h Select 1K VROM at PPU 0000h-03FFh A001h Select 1K VROM at PPU 0400h-07FFh A002h Select 1K VROM at PPU 0800h-0BFFh A003h Select 1K VROM at PPU 0C00h-0FFFh A004h Select 1K VROM at PPU 1000h-13FFh A005h Select 1K VROM at PPU 1400h-17FFh A006h Select 1K VROM at PPU 1800h-1BFFh A007h Select 1K VROM at PPU 1C00h-1FFFh A008h-A00Fh Unknown (always 01h, probably VROM bank related) C001h IRQ Counter/Start (MMC3, decremented per scanline, paused in VBlank) C002h IRQ Acknowledge (write any value) C003h IRQ Counter/Start (always write same value as to C001h) D000h Unknown (always 00h) E000h IRQ Enable (Bit0), upper 7bit unknown (always 0000011b) F000h Unknown (always 00h) |
| Mapper 118: MMC3 with different Name Tables |
Used by Goal 2, Pro Sport Hockey, Armadillo, and Ys III.
Name Tables working somehow different, otherwise same as MMC3:
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 119: MMC3 TQROM with VROM+VRAM Pattern Tables |
Used by Pinbot and High Speed. Consists of MMC3B plus 74HC32.
Allows to select between VROM and 8K VRAM as Pattern Tables (presumably by
certain VROM bank numbers?), otherwise same as MMC3:
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 122: Whatever |
No info. Don't have a ROM-image.
Reportedly "74161/32" used by "Madoola No Tsubasa".
Maybe "Madoola No Tsubasa" is same as "Wing of Madoola" (?)
Mapper 184: Sunsoft - VROM/4K
| Mapper 133: Sachen |
Used by Jovial Race.
4120h Memory Control
Bit1-0 Select 8K VROM at PPU 0000h-1FFFh
Bit2 Select 32K ROM at 8000h-FFFFh
|
Appears to be a variant of Mapper 113, with PRG ROM selection moved to Bit2.
| Mapper 151: VS Unisystem - PRG/8K, VROM/4K |
Used by VS Gradius and VS Goonies. On VS Unisystem arcade machines.
8000h Select 8K ROM bank at 8000h-9FFFh A000h Select 8K ROM bank at A000h-BFFFh C000h Select 8K ROM bank at C000h-DFFFh N/A Fixed 8K ROM bank at E000h-FFFFh E000h Select 4K VROM bank at PPU 0000h-0FFFh F000h Select 4K VROM bank at PPU 1000h-1FFFh |
VS Goonies and VS Gradius use Vertical Mirroring (hard-wired).
Note: Other VS Games use Mappers 1,2,68,99 and maybe other mappers.
The machine also includes special DIP-Switch and Credit I/O ports as
described in Controllers chapter.
| Mapper 152: Whatever |
The readme of Pocketnes (for Gameboy Advance) mentions existance Mappper 152.
No info. Don't have any ROM-images.
| Mapper 160: Same as Mapper 90 |
Seems to be duplicate/nonsense, same as Mapper 90, used by Aladdin.
Mapper 90: Pirate MMC5-style
| Mapper 161: Same as Mapper 1 |
Seems to be duplicate/nonsense, same as Mapper 1, used by Hanjuku Eiyuu.
Mapper 1: MMC1 - PRG/32K/16K, VROM/8K/4K, NT
| Mapper 180: Nihon Bussan - PRG HI |
Used by Crazy Climber.
8000h-FFFFh Memory Control
Bit7-3 Not used (always zero)
Bit2-0 Select 16K ROM bank at C000h-FFFFh (upper block!)
N/A Fixed 16K ROM bank at 8000h-BFFFh (always FIRST 16K bank)
|
Bus-conflicts.
| Mapper 182: Same as Mapper 114 |
| Mapper 184: Sunsoft - VROM/4K |
Used by Atlantis no Nazo, Kanshakudama, and Wing of Madoola.
6000h Select VROM Banks
Bit2-0 Select 4K VROM at PPU 0000h-0FFFh
Bit6-4 Select 4K VROM at PPU 1000h-1FFFh
|
| Mapper 185: VROM-disable |
Appears to be used for CNROM games with only one (used) 8K VROM bank,
however, VROM appears to be bigger than 8K, the games verify the the presence
of the unused (empty) VROM banks on startup, and get caught in an endless
loop if they do not exist.
8000h-FFFFh (De-)select VROM bank |
Values used to switch VROM on/off are:
Off On Title F0h 0Fh Bird Week 00h 33h B-Wings 00h 11h Mighty Bomb Jack 20h 22h Sansuu 1 Nen - Keisan Game 20h 22h Sansuu 2 Nen - Keisan Game 00h FFh Sansuu 3 Nen - Keisan Game 13h 21h Spy vs Spy |
Above games are working when mapping an empty VROM bank (FFh-filled) either when (X)=13h, or when (X AND 0Fh)=0.
| Mapper 188: UNROM-reversed |
Used by Karaoke Studio. Appears to be same as UNROM, but the first/second
128K are exchanged in the ROM-image (for unknown reason), ie. all bank
numbers (including the fixed "last" bank) are XORed by 08h.
Mapper 2: UNROM - PRG/16K
Or, maybe only the first 8 banks are used, and the further banks are garbage?
Bus-conflicts.
| Mapper 189: MMC3 Variant |
Used by Master Figher 2, and Street Fighter 2. There are three Master Fighter
2 versions, the 1st works as described below, the 2nd works but has distorted
background, the 3rd doesn't work - ROM addresses appear corrupted (?). And,
Street Fighter 2 works completely different - uses Ports 4132h for ROM, and
4122h/4123h for VROM (?) Anyways, the one working one works as such:
610xh Select 32K ROM Block (D7-D0 should match A7-A0, eg. [6103h]=03h) |
The rest of the mapper is same as MMC3 (for the selected block of memory),
Mapper 4: MMC3 - PRG/8K, VROM/2K/1K, VT, SRAM, IRQ
| Mapper 222: Dragon Ninja |
Used by a pirate copy of Dragon Ninja.
8000h Select 8K ROM at 8000h-9FFFh A000h Select 8K ROM at A000h-BFFFh N/A Fixed 16K ROM at C000h-FFFFh (last 16K) 9000h Unknown (always E0h = Vertical Mirroring) B000h/B001h Lower/upper 4bit of 1K VROM bank at PPU 0000h-03FFh B002h/B003h Lower/upper 4bit of 1K VROM bank at PPU 0400h-07FFh C000h/C001h Lower/upper 4bit of 1K VROM bank at PPU 0800h-0BFFh C002h/C003h Lower/upper 4bit of 1K VROM bank at PPU 0C00h-0FFFh D000h/D001h Lower/upper 4bit of 1K VROM bank at PPU 1000h-13FFh D002h/D003h Lower/upper 4bit of 1K VROM bank at PPU 1400h-17FFh E000h/E001h Lower/upper 4bit of 1K VROM bank at PPU 1800h-1BFFh E002h/E003h Lower/upper 4bit of 1K VROM bank at PPU 1C00h-1FFFh F000h IRQ Counter/Stop/Set/Ack F001h IRQ Counter/Stop/Set/Ack F002h IRQ Counter/Start (incrementing approx every 120 (?) cycles) |
| Mapper 225: X-in-1 |
Used by 52-in-1, 58-in-1, 64-in-1, 72-in-1, 110-in-1, 115-in-1 carts. The
reset vectors in all games are redirected to the game selection menu, and all
copyright messages have been shamelessly removed.
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A14,A5-0 Select 8K VROM bank at PPU 0000h-1FFFh
A14,A11-A6 Select PRG 2x16K ROM bank at 8000h-FFFFh
A12 Select PRG page size (0=32K, 1=16K)
0 32K page at 8000h-FFFFh (LSB/A6 of bank number ignored)
1 16K page mirrored to 8000h-BFFFh and C000h-FFFFh
A13 ?Mirroring select (0=Vertical, 1=Horizontal Mirroring)
A15 Must be "1"
5800h-5FFFh 4x4bit Register File (D0-D3 data bits, addressed via A0-A1)
|
The 4x4bit latch is used as 16bit "RAM", used to restore the old menu selection when re-entering the menu by pushing the Reset button.
A14 is shared for both PRG/VROM in larger 2048K+1024K carts (those with more
than 100 games), smaller 1024K+512K carts don't use A14.
| Mapper 226: X-in-1 |
Used by Super 42-in-1 (1024K), and 76-in-1 (2048K).
Typically booted with opcode 8E 8E 8E 00 - MOV [8E8E],X; BRK in RAM.
Mapper 226:
8000h,8E8Eh Memory Control
Bit4-0 Bank Number Bit4-0
Bit5 Mode
0 Map 32K ROM at 8000h-FFFFh (bank bits 6-1 used, bit0 ignored)
1 Map the same 16K ROM bank at both 8000h-BFFFh and C000h-FFFFh
Bit6 Name Table (0=Horizontal, 1=Vertical Mirroring)
Bit7 Bank Number Bit5
8001h Upper Bit of bank selection (2048K carts only)
Bit0 Bank Number Bit6
|
The "VROM" banks of the original games are contained in PRG ROM, and are copied to 8K VRAM at PPU 0000h-1FFFh when starting a game.
See also:
Mapper 233: X-in-1 plus Reset
Mapper 230: X-in-1 plus Contra
FROM 226.TXT
Mapper hardware is provided by five 74-series ICs; LS74A, LS273, LS139, LS02
and LS153. A diode and capacitor are arranged to reset the mapping when the
Reset button is pressed.
Register 1, Bit 1 - controls whether the CHR-RAM is write-protected:
0 - not write-protected
1 - write-protected
|
When the Reset button is pressed, both registers are reset to all zero bits.
| Mapper 227: X-in-1 |
Used by 1200-in-1 (a fake containing only 14 different games).
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A6-A2 Select 16K ROM at 8000h-BFFFh (X)
A1 Mirroring (0=Vertical, 1=Horizontal Mirroring)
A14-A13 Menu mode (00b=Menu, 11b=Other)
A9 128K Mode (1=128K, 0=Other)
A0 32K Mode (1=32K, 0=Other)
A11-A10,A8 Always 0
A12 Usually 1 (except when initializing VRAM for game)
A7 Usually 1 (except menu/contra/galaxian)
|
16K ROM at C000h-FFFFh is Bank 0 in Menu Mode (and on reset), Bank (X OR 1) in 32K Mode, Bank (X OR 7) in 128K Mode, or otherwise Bank (X) in 16K mode.
| Mapper 228: X-in-1 Homebrewn |
Used in two carts with incredible crude homebrewn games: Action 52 (multicart
52-in-1) and Cheetah Men 2 (single game cart).
8000h-FFFFh Memory Control (Decoded by address AND data lines)
A3-A0,D1-D0 Select 8K VROM at PPU 0000h-1FFFh
A12-A7 Select 32K ROM at 8000h-FFFFh
A14-A13,A6-A4,D7-D2 Not used (always zero)
5FF0h-5FF3h 4x4bit Register File (D0-D3 data bits, addressed via A0-A1)
|
The 4x4bit latch is used as 16bit "RAM", used to restore the old menu selection when re-entering the main menu (used in Action52 multicart only).
Notes
Action52 has an odd ROM-size of 1.5MB, Banks 30h-3Fh are probably mirrors.
There seems to be no Name Table control bit (unless it is shared with
bank-selection bits), most games look better at Vertical Mirroring (eg.
cheetahmen, silversword), though some look better at Horizontal Mirroring
(eg. criticalbp).
| Mapper 229: 31-in-1 |
Used by 31-in-1 (512K+256K).
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A4-A0 Bank Selection, shared for PRG and VROM:
Select 8K VROM bank at PPU 0000h-1FFFh
Select 16K ROM bank at 8000h-BFFFh and same bank at C000h-FFFFh
A selection of 01h works special, it maps 16K ROM banks 0 and 1,
and bank 1 VROM, used for Super Mario which has 32K PRG ROM.
A6-A5 Name Table
0 Two-Screen, Vertical Mirroring
1 Two-Screen, Horizontal Mirroring
2 Probably one-screen, used on boot
3 Probably one-screen, used in menu
A14 The menu sets this bit when accessing bank 0
|
| Mapper 230: X-in-1 plus Contra |
Used in a 640K ROM-image. The 1st 128K contain a single game (Contra), the
remaining 512K contain a 22-in-1 multicart. NB. the multicart menu also tries
to detect further ROM, and if any such found, displays a 63-in-one menu.
No idea if/how selection between Contra and 22-in-1 works. The 22-in-1 part
is identical with Mapper 226 (banks 0..31 located AFTER the 1st 128K):
Mapper 226: X-in-1
| Mapper 231: 20-in-1 |
Used by 20-in-1.
8000h-FFFFh Memory Control (Write any data, port decoded by address lines)
A7-A6 Name Table Setting (0-3)
0 Probably one-screen (used by menu only)
1 Two-Screen Vertical Mirroring
2 Two-Screen Horizontal Mirroring
3 Not used
A5 Always opposite of A1, ie. A5=(A0 XOR 1), probably 2nd chip-select
A4-A1 Select 32K ROM bank at 8000h-FFFFh
A0 Mode (0=Normal, 1=Mirror 1st half selected 32K bank to C000h-FFFFh)
|
The "VROM" banks of the original games are contained in PRG ROM, and are copied to 8K VRAM at PPU 0000h-1FFFh when starting a game.
There's also a version of the same cartridge with slightly different mapper:
Mapper 61: 20-in-1
| Mapper 232: 4-in-1 Quattro Camerica |
Used by Camerica 4-in-1 games with 256K ROM and 8K VRAM - Quattro Adventure,
Quattro Arcade, and Quattro Sports.
9000h Select 64K block for 8000h-FFFFh (block number in Bit4-3) C000h-Fxxxh Select 16K ROM bank at 8000h-BFFFh (within current 64K) N/A High 16K ROM bank at C000h-FFFFh (last 16K of current 64K) FFF0h,FFF1h Unknown - Write any value at proper timing (maybe lockout) |
In some (not all) ROM-images, 2nd/3rd game seem to be mis-exchanged.
| Mapper 233: X-in-1 plus Reset |
Used by "42 Games" which is almost the same as "Super 42-in-1" (Mapper 226,
which comes with separate 22 and 20 games menues, prompting the user to press
Select to switch to the next menu).
42 Games (1024K ROM) comes with a "Level 1-4" main menu, each "Level" allows
to select from 10 or 11 games. That main menu shows up only if the cartridge
detects a special reset function, if that detection fails, then it assumes to
be a 512K ROM, and enters a 22 or 20 games menu. That means, the cartridge
can be split into two fully functional 512K ROMs when removing the reset
function. That reset function appears to work like this:
FFFDh Reading from this address (the MSB of reset vector) destroys the
current Bank selection, probably setting it to a value of FFh, at
least anything different than 00h or 80h
|
Aside from the extra reset function, it is same as Mapper 226,
There's also ROM named "Unknown" numbered as Mapper 233 with other
functionality?
| Mapper 234: Maxi-15 |
Used by the AVE Maxi 15 Game Cartridge.
Registers are set by writing *or reading* certain locations. In the case of writing, the programmer would need to ensure that the written value and that put on the data bus by the program ROM do not conflict. |
On power-up, and when the Reset button is pressed, registers R1 and R2 are
cleared. R3 is not cleared when Reset is pressed. After R1 has been set to a
non-zero value, it cannot be changed until the Reset button is pressed.
FF80h-FF9Fh Configuration Register (R1)
Bit7 Name Table Control (0=Vertical, 1=Horizontal Mirroring)
Bit6 Page Mode ROM/VROM Size (0=32K, 1=64K)
Bit5-0 Select 32K ROM/VROM bank (LSB ignored in 64K Page Mode)
Bit5 is wired to /CS or /OE of the ROM chips, ie. both ROM
and VROM are disabled when bit5 is set (unless additional ROMs
would be connected to inverted Bit5, in larger carts).
FFE8h-FFF7h Memory Banking Register (R2)
Bit7 Not Used
Bit6-4 Select 8K VROM at PPU 0000h-1FFFh (Bit6 not used in 32K Page mode)
Bit3-1 Not Used
Bit0 Select 32K ROM at 8000h-FFFFh (Bit0 not used in 32K Page mode)
FFC0h-FFDFh Lockout Register (R3)
Initially it is not possible to access R3. This is only possible
after R1 has been set to a non-zero value.
Bit7-2 Not Used
Bit1 CIC RST
Bit0 CIC OUT
|
Memory-mapping hardware consists of eleven chips: 74LS273, 2x74LS322, 2x74LS175, 2x74LS138, 74LS30, 74HC08, 74HC04 and a 4053. There are several discrete components, mostly related to the CIC-defeating function.
| Mapper 240: C&E/Supertone - PRG/32K, VROM/8K |
Used by Jing Ke Xin Zhuan (via Port 4800h), and Sheng Huo Lie Zhuan (via Port
4120h, or alternately GNROM-style via Port 8000h-FFFFh with bus-conflicts).
4120h,4800h,8000h-FFFFh Memory Control
Bit7-6 Not used (always zero)
Bit5-4 Select 32K ROM at 8000h-FFFFh (initially any 32K bank)
Bit3-0 Select 8K VROM at PPU 0000h-1FFFh
|
| Mapper 241: X-in-1 Education |
Used by Education Games 18-in-1, and Study and Game 32-in-1.
8000h-FFFFh Select 32K ROM at 8000h-FFFFh (initially 1st 32K bank) 5FF0h-5FFFh/Write Unknown (No info) 5FF0h-5FFFh/Read Unknown (somewhat Bit6: 1=Ready/Okay) |
Both cartridges require a special keyboard controller, similar as the Famicom keyboard, but with different keyboard matrix.
Controllers - Keyboard
| Mapper 242: Waixing - PRG/32K, NT |
Used by Wai Xing Zhan Shi.
8000h-FFFFh Memory Control (Write any data, port decoded by address lines) A6-A3 Select 32K ROM at 8000h-FFFFh (initially 1st 32K bank) A1 Mirroring (0=Vertical, 1=Horizontal Mirroring) A7,A0 Always 1 A14-A8,A2 Always 0 |
Similar as Mapper 227 (without using the various memory modes though),
Mapper 227: X-in-1
| Mapper 243: Sachen Poker - PRG/32K, VROM/8K |
Used by Mei Nu Quan (Honey Peach), and Poker III 5-in-1.
4100h Index (0-7) 4101h Data for above index |
The separate register indexes are:
0 Unknown, always 00h 1 Unknown, always 00h 2 Bit3 of 8K VROM at PPU 0000h-1FFFh 3 Unknown, always 00h 4 Bit0 of 8K VROM at PPU 0000h-1FFFh 5 Select 32K ROM at 8000h-FFFFh 6 Bit2,1 of 8K VROM at PPU 0000h-1FFFh 7 Unknown, always 05h |
Formula for VROM Registers 2,4,6: Bank=(R2*8)+(R4 AND 1)+(R6 AND 3)*2
| Mapper 244: C&E - PRG/32K, VROM/8K |
Used by Decathlon only. Note: Cat Ninden Teyandee translations declared as
"Mapper 244" seem to be MMC3 games.
8000h-FFFFh Memory Control
Bit7 Not used (zero)
Bit6-4 Swap bits (some sort of confusion / copy protection, see below)
Bit3 Set ROM or VROM bank (0=ROM, 1=VROM)
Bit2-0 Select 32K ROM at 8000h-FFFFh or 8K VROM at PPU 0000h-1FFFh
|
Swap bits for ROM Bank Number:
Bit4=1: XOR bank number by 03h Bit5=1: Exchange bank number Bit0,1 Bit6=1: Not used |
Swap bits for VROM Bank Number:
Bit4=1, Bit5=1, Bit6=1: XOR bank number by 07h (without further exchanges) Bit4=0, Bit5=1, Bit6=1: Not used Bit4=1: Exchange bank number Bit 0,1 (processed first) Bit5=1: Exchange bank number Bit 1,2 Bit6=1; Exchange bank number Bit 2,0 (processed last) |
Bus-conflicts.
| Mapper 246: C&E - PRG/8K, VROM/2K, SRAM |
Used by Fong Shen Bang - Zhu Lu Zhi Zhan.
6000h Select 8K ROM at 8000h-9FFFh 6001h Select 8K ROM at A000h-BFFFh 6002h Select 8K ROM at C000h-DFFFh 6003h Select 8K ROM at E000h-FFFFh (initially probably last bank, or bank 3) 6004h Select 2K VROM at PPU 0000h-07FFh 6005h Select 2K VROM at PPU 0800h-0FFFh 6006h Select 2K VROM at PPU 1000h-17FFh 6007h Select 2K VROM at PPU 1800h-1FFFh |
The cartridge also contains SRAM at 6000h-7FFFh.
Not sure if SRAM at 6000h-6007h can be used.
| Mapper 255: X-in-1 - (Same as Mapper 225) |
Duplicated/nonsense mapper number, 255 is functional same as 225.
Mapper 225: X-in-1
| Famicom Disk System (FDS) |
Famicom Disk System (FDS) is a Famicom extension unit which was produced by
Nintendo and only sold in Asian countries. It consists of a disk drive
accepting 2.5" or 3" (?) floppies, 32K of RAM to load programs into, 8K of
VRAM, and some other hardware described below.
FDS Memory and I/O Maps
FDS I/O Ports - Timer
FDS I/O Ports - Disk
FDS I/O Ports - Sound
FDS BIOS Disk Format
FDS BIOS Disk Functions
FDS BIOS Disk Errors
FDS BIOS Data Areas in WRAM
FDS Disk Drive Operation
| FDS Memory and I/O Maps |
FDS Memory Map
4020h-40FFh I/O Ports (2C33) (Disk, Sound, Timer) 6000h-DFFFh 32K WRAM E000h-FFFFh 8K FDS BIOS ROM |
Caution: Parts of the FDS 32K WRAM, and of the built-in 2K WRAM are reserved for use by the FDS BIOS: 0000h-000Eh, 00F9h-0103h, and DFF6h-DFFFh.
FDS VRAM Map
0000h-1FFFh Pattern Tables - 8K VRAM |
Note: Horizontal/Vertical Name Table Mirroring can be selected via Port 4025h.
FDS I/O Map (2C33 Registers)
4020h Timer IRQ Counter Reload value LSB (W) 4021h Timer IRQ Counter Reload value MSB (W) 4022h Timer IRQ Enable/Disable (W) 4023h 2C33 I/O Control Port 4024h Disk Data Write Register (W) 4025h Disk Control Register (W) 4026h Disk External Connector Output (W) 4030h Disk Status Register 0 (R) 4031h Disk Data Read Register (R) 4032h Disk Status Register 1 (R) 4033h Disk External Connector Input (R) 4040h..407Fh Sound Wave RAM - 64 x 6bit sample data (R/W) 4080h Sound Volume Envelope (W) 4082h Sound Wave RAM Sample Rate LSB (W) 4083h Sound Wave RAM Sample Rate MSB and Control (W) 4084h Sound Sweep Envelope (W) 4085h Sound Sweep Bias (W) 4086h Sound Modulation Frequency LSB (W) 4087h Sound Modulation Frequency MSB (W) 4088h Sound Modulation Table (W) 4089h Sound Wave RAM Control (W) 408Ah Sound Envelope Base Frequency (W) 4090h Sound Current Volume Gain Level (6bit) (R) 4092h Sound Current Sweep Gain Level (6bit) (R) |
| FDS I/O Ports - Timer |
Interrupt Timer intended to produce mid-screen scanline interrupts.
4020h - Timer IRQ Counter Reload value LSB (W)
4021h - Timer IRQ Counter Reload value MSB (W)
Reload value loaded to actual 16bit counter register on write to 4022h, and on counter underflow. Counter is decremented once per CPU clock cycle. |
4022h - Timer IRQ Enable/Disable (W)
Bit1 Enable (0=Stop/Acknowledge Timer IRQ, 1=Start/Enable Timer IRQ) |
Note: Timer IRQ Flag is found in Bit0 of Port 4030h, Disk Status Register 0).
The IRQ Vector is controlled by the BIOS via [0101h] and [DFFEh],
FDS BIOS Data Areas in WRAM
| FDS I/O Ports - Disk |
Disk access can be handled by using the FDS BIOS, so there's usually no need
to write to below ports directly, the only exception would be the Screen
Mirroring flag, to change it: Read the current value from [FAh], change Bit3,
then write the new value to both [FAh] and [4025h].
4025h - Disk Control Register (W) (Read-able copy in WRAM at 00FAh)
Bit0 Drive Motor (0=On, 1=Off)
When active (0), causes disk drive motor to stop. During this time,
$4025.1 has no effect. Uh, Active=0=Stop ?
Bit1 \ = Set drive head to the start of the first track.
When active (0), causes disk drive motor to turn on. This bit must stay
active throughout a disk transfer, otherwise $4032.1 will always return 1.
When deactivated, disk drive motor stays on until disk head reaches most
inner track of disk.
Bit2 Disk Data Direction (0=Write, 1=Read)
Bit3 Screen Mirroring (0=Vertical, 1=Horizontal Mirroring)
Bit4 Enable CRC Phase (0=Read/Write Data, 1=Verify/Write CRC)
Bit5 Unknown (Should be always 1)
Bit6 GAP Control, Read Mode: 1=Reset CRC, and wait for end of GAP.
Write Mode: 1=Reset CRC, and start writing data. 0=Write GAP (zeros)
Bit7 Disk IRQs on every byte transfer (0=Disable, 1=Enable)
|
4030h - Disk Status Register 0 (R)
Bit0 Timer IRQ Flag (0=None, 1=IRQ: Timer Underflow)
Bit1 Disk IRQ Flag (0=None, 1=IRQ: Request Data Transfer via 4024h/4031h)
Reset when $4024, $4031, or $4030 has been serviced.
Bit4 CRC Status (0=Okay, 1=Error, Checksum at end of block not matching)
Bit6 Lost Data (0=Okay, 1=Error, CPU didn't process 4024h/4031h in time)
Bit7 Unknown
|
4032h - Disk Status Register 1 (R)
Bit0 Disk Presence (0=Inserted, 1=Not inserted) Bit1 Disk Rewind Flag (0=Ready/Playback, 1=Rewind Active) Bit2 Write Protection (0=Writeable, 1=Read-only, or Disk not inserted) Bit6 Usually 1 (probably relict of recent opcode byte) |
4031h - Disk Data Read Register (R)
4024h - Disk Data Write Register (W)
8bit data received from / to be written to disk (least significant first). |
Note: Disk IRQ Flag indicates when next byte is to be transferred.
4026h - External Connector Output (W) (Read-able copy in WRAM at 00F9h)
4033h - External Connector Input (R) (Inputs work only if Outputs=High)
Bit0-6 External Connector Pins 3-9 (0=Low, 1=High/Input) Bit7 Power Good (0=Okay, 1=Battery power low) |
Port 4026h should output High to any input pins, especially Bit7 should be always set to configure Power Good as input.
4023h - 2C33 I/O Control Port
Bit0 Disk I/O (0=Disable, 1=Enable) Bit1 Sound (0=Disable, 1=Enable) |
| FDS I/O Ports - Sound |
4040h..407Fh - Wave RAM - 64 x 6bit sample data (Read/Write)
Writes to these registers are ignored unless Write Mode is turned on (see
register 4089h).
4089h - Wave RAM Control (Write Only)
Bit7 Wave Write Mode (1=Stop Sound output & Allow to write to Wave RAM) Bit6-2 Not used Bit1-0 Master Volume (0-3 = 100%,66%,50%,40% = 30/30,20/30,15/30,12/30) |
4082h - Wave RAM Sample Rate LSB (Write Only)
Bit7-0 Lower 8 bits of the main unit's frequency (upper 4 bits in 4083h) |
4083h - Wave RAM Sample Rate MSB and Control (Write Only)
Bit7 Main Unit disable (0=Enable, 1=Disable Sound Output) Bit6 Envelope disable (0=Normal, 1=Disable Volume/Sweep Envelopes) Bit5-4 Not used Bit3-0 Upper 4 bits of the main unit's frequency |
Main Unit / Sample Rate: (per entry of the 64-entry wave ram)
F = 1.79MHz * (Freq + Mod) / 65536 Mod = Frequency change based on the Modulation unit |
If the 12bit frequency is zero, the Main unit is disabled (channel silent).
408Ah - Envelope Base Frequency (Write Only)
Bit7-0 Envelope Base Frequency, Fbase=1.79MHz/8/N |
Fbase used by 4080h and 4084h. Volume/Sweep Envelope are disabled if N=0.
4080h - Volume Envelope (Write Only)
Bit7 Volume Envelope Mode (0=Volume Envelope, 1=Fixed Volume)
Bit6 Volume Envelope Direction (When enabled / at specified rate)
0=Decrease Volume by 1 (only if Volume>00h)
1=Increase Volume by 1 (only if Volume<20h)
Bit5-0 When Bit7=1: Volume Level (0-20h=Muted-Loudest, 21h-3Fh=Same as 20h)
Bit5-0 When Bit7=0: Volume Envelope Rate, F=Fbase/(N+1)
|
The volume level can be set to 00h-3Fh by write with Bit7=1, this level is also used as initial volume when switching to envelope mode by setting Bit7=0.
In decrease mode, initial values 21h-3Fh are resulting delayed decrease;
volume stays at maximum level until the value gets smaller than 20h.
4084h - Sweep Envelope (Write Only)
Bit7 Sweep Envelope Disable (1=Disable) Bit6 Sweep Envelope Mode (0=Decrease, 1=Increase sweep gain) Bit5-0 When Bit7=1: Sweep Gain Bit5-0 When Bit7=0: Sweep Envelope Rate, F=Fbase/(N+1) |
4085h - Sweep Bias (Write Only)
Bit7 Not used Bit6-0 Sweep Bias (signed 7bit; -40h..+3Fh) |
Sweep Bias is a used by the Modulation unit in calculating frequency bend.
Sweep Bias negative: Modulation unit will be bending frequency down.
Sweep Bias positive: Modulation unit will be bending frequency up.
Any write to Sweep Bias register resets Modulation Unit's address to zero.
This address is used by the Modulation Unit when looking up entries written
to the Modulation table (via $4088).
4086h - Modulation Frequency LSB (Write Only)
Bit7-0 Lower 8bit of 12bit Modulation frequency |
4087h - Modulation Frequency MSB (Write Only)
Bit7 Modulation Enable/Disable (0=Enable, 1=Disable) Bit6-4 Not used Bit3-0 Upper 4bit of 12bit Modulation frequency |
Modulation Unit: Modulation Rate (per entry of the 64-entry modulation table)
F = 1.79MHz * ModFreq / 65536 |
If the 12bit frequency is zero, the Modulation unit is disabled.
4088h - Modulation Table (Write Only)
Bit7-3 Not used Bit2-0 Modulation input |
Writing to this register puts the value written at the END of the modulation table **twice**, and shifts each entry already in the table 2 places to the front. The first 2 entries of the Modulation table are shifted out and lost.
old, old <-- ModTable_0 <-- ModTable_1 <-- ... <-- ModTable_63 <-- new, new
4090h - Current Volume Gain Level (6bit) (Read Only)
4092h - Current Sweep Gain Level (6bit) (Read Only)
4023h - 2C33 I/O Control Port
Bit0 Disk I/O (0=Disable, 1=Enable) Bit1 Sound (0=Disable, 1=Enable) |
FDS Sound by Disch, Release 1, 07/14/2004, based on info from Nori.
Sweep Envelope and Modulation Units
Sweep Envelope unit behaves just like the Volume Envelope, only it alters
Sweep Gain instead of Volume Gain. The Envelope Unit never pushes Sweep Gain
above $20, but it still can get above $20 if set that way via $4084.
Increase/Decrease mode is determined by bit 6 of $4084 |
Sweep Gain is used when calculating the Frequency change in the Modulation Unit...
The Modulation Unit, when clocked, takes 1 step through the Modulation Table
(set by writes to $4088). The Sweep Bias is adjusted based on the 3-bit
value in the table:
0:Bias=Bias+0 1:Bias=Bias+1 2:Bias=Bias+2 3:Bias=Bias+4 4:Bias=0 5:Bias=Bias-4 6:Bias=Bias-2 7:Bias=Bias-1 |
The address of the Modulation unit is incremented so that next clock it will use the next 3-bit value in the table. This address wraps at 64 and can be reset to zero by any write to $4085.
Sweep Bias wraps to fit within a signed 7-bit value, if it goes greater than
63, it wraps around to -64, and if it goes below -64, it wraps to 63.
The Modulation Unit works by altering the Frequency of the Main Unit by a
value calculated from the Sweep Gain and Sweep Bias values:
temp = Sweep_Bias * Sweep_Gain;
if temp AND 0Fh then
if Sweep_Bias<0 then temp=temp-10h else temp=temp+20h
temp=temp/10h
if temp>193 then temp -= 258; // not a typo... for some reason the wraps
if temp<-64 then temp += 256; // are inconsistent
Mod = Freq * temp / 64;
|
In this code, Freq is the 12-bit MAIN UNIT frequency, and Mod is the amount that frequency is altered. This generated 'Mod' value is used in the frequency calculation of the main unit (given earlier):
Hz = NES * (Freq + Mod) / 65536 |
If at any time the Modulation unit is off, 'Mod' is zero. Otherwise 'Mod' is the above calculated value. If Freq + Mod produces a number less than or equal to zero, the channel is presumably silenced.
Unit Activity
There are many factors that could disable a unit, here's an overview section
to cover all the needed requirements for the channel to be active.
Remember that each unit can be active regardless of the activitiy of other
units. For example... even though the main unit is off and the channel is
silent, this does not mean the Volume Envelope or Modulation units are
inactive.
If any of the supplied conditions are false... the unit is inactive and will
not be clocked. All conditions must be true for the unit to be active.
Volume Envelope Unit:
- Volume Envelope must be enabled (bit 7 of $4080 must be off) - Envelope Speed must be nonzero (set by $408A) - Envelope must be enabled (bit 6 of $4083 must be off) |
Sweep Envelope Unit:
- Sweep Envelope must be enabled (bit 7 of $4084 must be off) - Envelope Speed must be nonzero (set by $408A) - Envelope must be enabled (bit 6 of $4083 must be off) |
Modulation Unit:
- Modulation must be enabled (bit 7 of $4087 must be off) - Modulation frequency must be non-zero (set by $4086/$4087) |
Main Unit (Wave RAM Sound Output):
- Main Unit must be enabled (bit 7 of $4083 must be off) - Main Unit Frequency must be non-zero (set by $4082/$4083) - 'Freq + Mod' must be greater than zero (see Frequency Calculation section) - Write Mode must be off (bit 7 of $4089 must be off) |
| FDS BIOS Disk Format |
Each disk has two sides, each side having a capacity of circa 64K, typically
less than 64K data because some space is used for gaps and headers, also the
exact capacity may vary depending on the transfer rate/rotation speed of the
drive that has recorded the disk. To change an active side, the disk has to
be removed, flipped, and inserted back into the drive.
The drive doesn't support random access, and the disk is NOT split into
tracks and sectors. The data is stored sequentially on a single "track" which
is wound in a spiral, starting at the outer edge, towards the center of the
disk.
Side Header Block (56 bytes) (1st block on disk)
00h Block Type (01h)
01h-0Eh Disk ID (Must be ASCII string "*NINTENDO-HVC*")
0Fh Maker ID
10h-13h Game Name (usually 4 letter ASCII)
14h Version Number (usually 00h)
15h Side Number (00h=Side A, 01h=Side B) (00h=bootable)
16h Disk Number (00h=First, 01h=Second, etc.) (00h=bootable)
17h-18h Extra Disk ID Field
19h Highest File ID for Boot files (all files whose File ID is less
or equal than this value are loaded automatically on power-up)
1Ah-37h Reserved Space (30 bytes, ignored by BIOS)
|
File Number Block (2 bytes) (2nd block on disk)
00h Block Type (02h) 01h Number of Files on this side |
File Header Block (16 bytes) (for each file, 3rd,5th,7th... block on disk)
00h Block Type (03h) 01h File Number (00h=First file on this side, 01h=Second, etc.) 02h File ID (used to access files by Load Files function) 03h-0Ah File Name (not used, the BIOS access files by above File ID) 0Bh-0Ch Target Address (LSB, MSB) 0Dh-0Eh File Size (LSB, MSB) 0Fh Target Area (00h=WRAM, Other=VRAM) |
File Data Block (1+LEN bytes) (for each file, 4th,6th,8th... block on disk)
00h Block Type (04h) 01h-LEN Data (LEN=File Size in File Header Block) |
Gaps, Start Bits, CRC Values
Each block is preceded by a GAP (a stream of "0" bits), followed by a Start
Bit ("1"), followed by the actual bytes contained in the block, followed by a
16bit CRC value.
| FDS BIOS Disk Functions |
Disk Boot
On power-up, the FDS call the Load Files function to load the boot files. The
DiskID is FFh-filled (wildcards), except the Side Number and Disk Number
entries which must be both 00h on boot-able disks. LoadList is empty,
indicating to load all boot files, ie. all files whose File ID is less or
equal than the Boot ID value defined in Disk Header block.
There must be at least two boot files on the disk, one containing the program
with entrypoint (16bit pointer, which must be loaded to DFFCh), the other
file containing the Nintendo License string (E0h bytes, which must be loaded
to PPU 2800h, and which is verified against copy in BIOS at ED37h).
DiskID
Used by most BIOS functions to ensure that the correct disk/side is inserted.
DiskID consists of 10 bytes which are compared against Disk Header Block
[0Fh..18h]. Each DiskID byte may be set to FFh, which is used as wildcard,
comparision always passes okay for that bytes. If the comparision does not
match then error codes 04h..10h are returned, indicating which entry didn't
match.
E1F8h - Load Files
The function scans <all> files on disk, respectively, the execution time is
the same, no matter how many/how large files are loaded. On the contrary,
multiple calls to LoadFiles would be unneccessarily slow.
RETaddr: pointer to DiskID RETaddr+2: pointer to LoadList A on return: error code Y on return: count of files actually found |
LoadList is a list of up to 20 File IDs, if the list contains less than 20 IDs then it must be terminated by FFh. If LoadList is empty (FFh in the first byte) then the boot files are loaded, that are all files whose File ID is less or equal than the Boot ID value which is defined in the Disk Header.
E32Ah - Get Disk Information
RETaddr: pointer to DiskInfo A on return: error code |
The DiskInfo pointer should point to a free memory location, which will receive the following data:
0Ah bytes Disk Header Block [0Fh..18h], manufacturer, disk name, etc. 1 byte File Number Block [01h], number of files on disk (N) N*9 bytes File Header Block [02h..0Ah], File ID and Filename, for each file 2 bytes Disk Size (MSB,LSB) |
Disk size is equal to the sum of each file's size entry, plus an extra 261 per file.
E237h - Append File
Sets A=FFh (append after last file), ie. same as A=FileCount, then continues
at E239h (Write File).
E239h - Write File
Register A specifies how many old files are to be kept preserved on disk,
these files are read/skipped, and the new file is then written to disk after
those files, and the disks FileCount is set to A+1, making the new file to be
the last file on disk, any further files are deleted/hidden.
In a second cycle, the written data is verified, if the verification fails
(error 26h), then the file count is decremented, ie. the new file is deleted.
RETaddr: pointer to DiskID RETaddr+2: pointer to FileInfo A on call: File Number (00h=First) (FFh=Append after last file) A on return: error code |
FileInfo occupies 17 bytes, the first 14 bytes contain File Header entries [02h..0Fh], ie. File ID, Filename, Load Address, Filesize, and Load Area.
The last 3 bytes contain the Source Address and Source Area (which may or may
not be same as Load Address and Load Area).
E2BBh - Adjust File count
RETaddr: pointer to DiskID A on call: number to reduce current file count by A on return: error code Special error: #$31 if A is less than the disk's file count |
Reads in disk's file count, decrements it by A, then writes the new value back.
E2B7h - Check File count
RETaddr: pointer to DiskID A on call: number to set file count to A on return: error code Special error: #$31 if A is less than the disk's file count |
Reads in disk's file count, compares it to A, then sets the disk's file count to A.
E305h - Set File count (alt. 1)
RETaddr: pointer to DiskID A on call: number to set file count to A on return: error code |
Sets the disk's file count to A.
E301h - Set File count (alt. 2)
RETaddr: pointer to DiskID A on call: number to set file count to minus 1 A on return: error code |
Sets the disk's file count to A+1.
Don't expect disk calls to return quick; it may take several seconds to
complete. The ROM BIOS always uses disk IRQ's to transfer data between the
disk, so programs must surrender IRQ control to the ROM BIOS during these
disk calls. The value at [$0101] however, is preserved on entry, and restored
on exit.
WRAM Target Addresses
Target Addresses should be in range 0200h-07FFh or 6000h-DFFFh. The BIOS
rejects (silently ignores) most attempts to load data to 0000h-01FFh. In
particular, it rejects Target Addresses at 0-1FFh (including mirrors at
800h,1000h,1800h), it also rejects wraps from FFFFh to 0000h.
However, it does not reject wraps to mirrors (eg. from 7FFh to 800h), clever
use of this feature might allow to modify values on stack, and to bypass the
Boot License.
Furthermore, target address 2000h can be used to enable NMIs during loading,
the games Bislot, Bisyosya, and Bishojo Control are using this trick to abort
the boot process and to start the game - without Boot License - via NMI
vector at [DFFAh].
VRAM Source/Target Addresses
Mind that the screen should be disabled when loading/writing VRAM data, Port
2001h/Bit3-4 should be zero, otherwise VRAM could be accessed only in VBlank.
Mind that physical content of VRAM addresses 2400h-2BFFh changes depending on
current mirroring. The BIOS re-initializes parts of VRAM after loading the
boot files on power up, overwriting any boot-files loaded to that areas.
Boot License String
32x7 characters in VRAM 2800h-28DFh (and copy in BIOS at ED37h)
" NINTENDO r " " FAMILY COMPUTER TM " " " " THIS PRODUCT IS MANUFACTURED " " AND SOLD BY NINTENDO CO;LDT. " " OR BY OTHER COMPANY UNDER " " LICENSE OF NINTENDO CO;LTD.. " |
By using Non-ASCII BIOS Tile Numbers: A..Z=0Ah..23h SPC=24h .=26h ;=27h r=28h.
See WRAM Target Addresses above for methods to bypass the Boot License.
| FDS BIOS Disk Errors |
Error codes are returned in both A and X registers (plus zero flag, Z=okay)
00h Okay (no error) (zero flag set) 01h No disk inserted (Port 4032h, Bit0) 02h No battery/power (Port 4033h, Bit7) 03h Disk write-protected (Port 4032h, Bit2) 04h Bad Side Header [0Fh], Maker ID 05h Bad Side Header [10h..13h], Game name 06h Bad Side Header [14h], Game version 07h Bad Side Header [15h], Side number (flip the disk) 08h Bad Side Header [16h], Disk number 09h Bad Side Header [17h], Extra ID Value 1 10h Bad Side Header [18h], Extra ID Value 2 20h Bad Nintendo License String (must be loaded to PPU 2800h-28DFh on boot) 21h Bad Side Header [01h..0Eh], Disk ID (must be "*NINTENDO-HVC*") 22h Bad Side Header [00h], Block ID must be 01h 23h Bad File Number [00h], Block ID must be 02h 24h Bad File Header [00h], Block ID must be 03h 25h Bad File Data [00h], Block ID must be 04h 26h Write-Verify Error (verification of written data failed) 27h Block CRC Read Failure (Port 4030h, Bit 4) 28h Lost Data (Port 4030h, Bit 6), CPU didn't read from 4031h in time 29h Lost Data (Port 4030h, Bit 6), CPU didn't write to 4024h in time 30h Disk Full (Port 4032h, Bit 1), Disk head has reached most inner track 31h Data number of a disk doesn't match up (?) |
| FDS BIOS Data Areas in WRAM |
The BIOS uses several places in memory, but only some of them are expected
to be maintained by game code.
Addr Size Expl. |
Scratch Area (destroyed by any calls to BIOS disk functions)
0000h 2 first 16bit parameter 0002h 2 second 16bit parameter 0004h 1 previous stack frame 0005h 1 error retry count 0006h 1 file counter 0007h 1 current block type 0008h 1 boot ID code 0009h 1 dummy read flag 000Ah 2 16bit destination address 000Ch 2 16bit transfer length count 000Eh 1 file found counter |
Copies of I/O Ports (used to READ content of Write-Only I/O Ports)
The BIOS does (and the game should) keep these bytes in sync with the ports.
00F9h 1 value last written to [$4026] $FF on reset (disk ext connector) 00FAh 1 value last written to [$4025] $2E on reset (disk control) 00FBh 1 value last written to [$4016] 0'd on reset (joypad) 00FCh 1 value last written to [$2005]#2 0'd on reset (ppu scrolling) 00FDh 1 value last written to [$2005]#1 0'd on reset (ppu scrolling) 00FEh 1 value last written to [$2001] $06 on reset (ppu control) 00FFh 1 value last written to [$2000] $80 on reset (ppu control) |
IRQ/NMI/Reset Control
0100h 1 Action on NMI (set to C0h on reset) 0101h 1 Action on IRQ (set to 80h on reset) 0102h 2 Action on Reset (AC35h after disk-boot, 5335h after warm-boot) |
IRQ/NMI/Reset Vectors
DFF6h 2 Game NMI vector 1, used if [0100h]=01xxxxxxb DFF8h 2 Game NMI vector 2, used if [0100h]=10xxxxxxb DFFAh 2 Game NMI vector 3, used if [0100h]=11xxxxxxb DFFCh 2 Game Reset vector, used if [0102h]=5335h or =AC35h DFFEh 2 Game IRQ vector, used if [0101h]=11xxxxxxb |
If [0100h..0102h] don't match then the IRQ/NMI/Reset is handled internally by the BIOS, without using (and without changing) the Game vectors.
Address DFFCh contains the initial entrypoint at disk boot, and is also used
as warm-boot vector when pushing the Reset button at a later time.
There may be more structured data areas in the zero page (for example, the
BIOS joypad routines use $F5..$F8 for storing controller reads), but only
the listed ones are used by the disk call subroutines.
| FDS Disk Drive Operation |
When the head reaches the end of the disk (most inner track), it returns to
the beginning of the disk (most outer track) and the cycle repeats, upon
request from the RAM adaptor. This means that on every scan, the entire disk
is read (which takes about 6 seconds). The disk drive signals the RAM adaptor
when the head has been positioned to the outer most track, and is starting a
new scan.
FDS data transfer protocol
Like most disk drive units, the FDS disk drive is sending it's data out via
serial connection.
1.Data ------------__________________------______------ 2.Rate ---___---___---___---___---___---___---___---___ 3.XOR ___---___------___---___---______------______--- 4.Write ___------_________------_________------------___ 5.Read ___-_____-________-_____-________-___________-__ |
The 1st row shows a 8bit data value, in this example A3h, or 10100011b, transferred LSB first. The 2nd row shows the transfer rate clock. The data/rate signals are XORed, as shown in the 3rd row. The actual signal written to disk is shown in the 4th row, magnetic polarity changes on any Low-to-High transitions of the XOR-signal. When reading from disk, spikes of one microsecond length are received on any polarity changes, as shown in the 4th row.
The RAM adaptor expects a transfer rate of 96.4kHz, although the tolerance it
has for this rate is +/- 10%. This tolerance is neccessary since, the disk
drive can NOT turn the disk at a constant speed.
First GAP
The length of the first GAP period present on typical FDS disks (relative to
the instant the disk drive's "-ready" signal is activated) is about 40000
bits, after which the first block start mark (indicating the beginning of the
first file) will appear.
The disk drive unit signals the RAM adaptor when the head has moved to the
beginning of the disk via the "-ready" signal it sends out (more on this
later). The "-ready" signal is based on a mechanical switch inside the drive
which is activated when the head is brought back to the outer most edge of
the disk (the beginning). Because the switch will usually be triggered
prematurely, the first 13000 bits (approx.) of data the drive will send out
immediately after this switch is activated will be invalid. To compensate for
this, the RAM adaptor purposely ignores the first 26100 bits (approx.) sent
to it since it recieves the "-ready" signal from the disk drive.
Further GAPs
The typical GAP period size used between files on FDS disks is roughly 976
bits (this includes the bits that are ignored by the RAM adaptor).
the RAM adaptor always ignores the first 488 bits (approx.) to follow after
the immediate end of any file. This period allows the RAM adaptor (or the
game rather) an oppertunity to make the switch from reading from the disk to
writing or vice-versa.
Final "GAP"
- The rest of the disk is filled with 0's after the last file is recorded
(although it really shouldn't matter what exists on the disk after this).
CRC calculation
CRC appended to the immediate end of every file. The CRC is 16-bits, and is
generated with a 17 bit poly. The poly used is 10001000000100001b (the X25
standard). Right shift operations are used to calculate the CRC (this
effectively reverses the bit order of the polynomial, resulting in the 16-bit
poly of 8408h). The file this algorithm is designed to work on has no block
start mark in it ($80), and has 2 extra bytes at the end (where a CRC
calculation would normally reside) which are 0'd. While the block start mark
is actually used in the calculation of a FDS file CRC, you'll see in the algo
below that the block start mark ($80) is moved directly into a register.
// ax is used as CRC accumulator
// si is the array element counter
// di is a temp reg
// Size is the size of the file + 2 (with the last 2 bytes as 0)
// Buf points to the file data (with the 2 appended bytes)
mov ax,8000h // this is the block start mark
sub si,si // zero out file byte index ptr
@@lop1:
mov dl,byte ptr Buf[si]
inc si
REPT 8
shr dl,1; rcr ax,1; sbb di,di; and di,8408h; xor ax,di
ENDM
cmp si,Size
jc @@lop1
|
// ax now contains the CRC.
Special thanks to Val Blant for assistance in cracking the CRC algorithm used
by the FDS.
- Some unlicenced FDS games activate the "-stop motor" signal (and possibly
even "-write", even though the storage media is not intended to be written
to) when a media transfer is to be discontinued, while "-scan media" is still
active. While this is an unorthodoxed method of doing this, the best way to
handle this situation is to give the "-stop motor" signal priority over any
others, and force data transfer termination during it's activation.
- Check out the FDS loader project (which uploads *.FDS files to the RAM
adaptor) for source code to my working disk drive emulator.
Hardware disk copy protection
Apparently, Nintendo had designed FDS disk drive units so that they cannot
reprogram entire disks, while still somehow being able to write the contents
of individual files to the end of disks. Now, there's alot of undocumented
things going on inside the disk drive unit, so I'm just going to say that
there are two evil IC's you've got to watch out for inside the FDS disk
drive- the 3213, and the 3206. There is a collection of 6 "FDS-COPY" jpegs
over at NESdev which (pg. 4 right side, and pg. 5) give a pretty graphic
overview of the steps involved in modding a stock FDS disk drive, so that it
may reprogram disks. Although I haven't built the specific circuit described
in the jpegs, I had designed & built a similar working circuit to defeat the
FDS's evil copy protection circuitry, with excellent results.
Software disk copy protection
Special thanks to Chris Covell for bringing this to attention.
Apparently, some FDS disks implement a very simple copy protection scheme,
which the game relies on in order for the game to refuse to work on the
copied disk. Normally, the number of files that exist on an FDS disk is
stored in the second block recorded on it. However, some games maintain
"invisible" files, which are basically files that exist beyond what the file
count number in the file count block indicates. This poses somewhat of a
problem for copy software like FDSLOADR, since these tools rely on the file
count block, and don't assume that there is any valid data past the last file
found on the disk. This means that when these types of disks are copied, the
invisible files will be lost, and when the game loads the files that do
exist, the game's going to give the user heat about there being a file
missing or somthing, gumming up the works. However in practice, when an FDS
disk is programmed, the unused end of the disk is usually completely zeroed
out, and this makes detecting the end of the disk simple: just wait to find a
GAP period of extreme length. Except in rare cases, this model for detecting
the true end of an FDS disk should generally provide the best results for
copying the complete contents for all types of FDS disks.
[That may be as well a trick to improve disk boot speed, not necessarily a
copy protection.]
Physical disk lockout mechanism
Ever wonder why Nintendo engraved their company's name along the handle edge
of all FDS disks? Inside the FDS disk drive bay, sitting just behind the
lower part of the front black plastic faceplate, is a little plastic block
with the letters "Nintendo" carved out of a hard plastic block. This
basically forces disks that don't have holes in those locations from
completely loading into the drive, circumventing usage. Now while many
companies made FDS disks with those holes cut out, I'm sure there must be
some disks out there that are compatable with the FDS, but don't have the
holes. So, the solution is to simply disassemble the FDS disk drive, remove
the disk cage, and remove the two screws securing the "Nintendo" letterblock.
| Nintendo Playchoice 10 |
Nintendo Playchoice 10 Hardware Description v0.2 by Oliver Achten
Overview
The Nintendo Playchoice 10 hardware consists of 2 main parts: the control and
the game part. The control part is driven by a Z80 CPU, which handles the
game selection, menu display and controls the game part. The game part is
100% compatible to the NES game console, using a N2A03 CPU and a N2B03 PPU.
Z80 Memory Map
0000h-3FFFh 16KB BIOS ROM 8000h-87FFh 2KB Work RAM 8800h-8FFFh 2KB Battery backed RAM 9000h-97FFh 2KB Video RAM (write only) C000h-DFFFh 8Kb Cartridge BIOS (resides on each game cartridge) E000h-FFFFh Protection |
Z80 I/O Map - READ (by IN opcodes)
00h Button/Status
bit 0: Channel select button
bit 1: Enter button
bit 2: Reset button
bit 3: N2A03 interrupt detect
bit 4: <zero>
bit 5: Coin 2 button
bit 6: Service button
bit 7: Coin 1 button
01h DIP-switch 1, Bits 0-7
02h DIP-switch 2, Bits 0-7
03h Reading from this address clears Bit 3 of read port 00h
|
Z80 I/O Map - WRITE (by OUT opcodes) (all write ports are using bit 0 only)
00h VRAM Access (0=by Z80 CPU, 1=by Video circuit)
01h Game Controls (0=Disable, 1=Enable)
02h PPU N2B03 Display output (0=Disable, 1=Enable)
03h APU N2A03 Sound output (0=Disable, 1=Enable)
04h Reset N2A03 CPU (0=Reset, 1=Run)
05h Stop N2A03 CPU (0=Stop, 1=Run)
06h Display Output Select (0=Z80/Video circuit, 1=N2B03 PPU)
(Only on single monitor version)
08h Z80 NMI Control (0=Disable, 1=Enable)
09h Watchdog Control (0=Enable, 1=Disable)
0Ah N2B03 PPU Control (0=Reset PPU, 1=Run PPU)
0Bh-0Eh Bits 0-3 of Game Channel Select (0-9)
0Fh Upper KB of battery ram (0=Disable, 1=Enable)
|
Video circuit
Video ram resides at $9000 - $97FF, and can only be accessed by the Z80 when
bit 0 of write port $00 is 0 (which also turns off the display). The screen
matrix consists of 32*28 characters. Due to the design of the video circuit,
the first visible line starts at $9080. Character and color codes are stored
in two bytes: byte 0 - cccccccc byte 1 - pppppccc (bit 0 - 7)
c: character code ($000 - $7FF) p: color code ($00 - $1F) |
The video circuit generates a nmi each vertical blank (when port $40 is set to 1). Screen refresh is 60 Hz.
Watchdog
When enabled by port $09, the watchdog resets the Z80 cpu after 8 screen
refreshes, which shall prevent a machine lockup. The watchdog is reset by
toggling port $09 from 0 to 1, which should be done by the nmi routine.
Game part
As mentioned before, the game part consists practically of a whole NES.
Memory map and registers are the same, however, the PPU is different since it
has seperate RGB and SYNC outputs, which provide a MUCH clearer picture than
the N2A02 NES PPU. Unlike VS Unisystem PPU, the Playchoice 10 PPU holds the
same color palette than its NES equivalent, so the game part of the
Playchoice 10 can be considered 100% NES compatible!
Ports 0Bh-0Eh determine which one of the 10 game slots is activated. It
affects also the C000h-FFFFh area in the Z80 memory map (cartridge bios and
protection).
Protection
Protection is done by a RP5H01 unit. No technical description...
Theoretically, it holds 16 bytes of data, which is accessed by both system
and cartridge bios.
Theoretically, the unit would not need the protection when a new Z80 bios is
written (Oliver Achten has written such a bios, so check out the web), which
would allow the possibility of building a NES cart adaptor for the PC 10.
| Unpredictable Things |
Reading Garbage from unused PPU Bits
Semi-stable garbage is returned for 8bit write-only PPU registers (2000h,
2001h, 2003h, 2005h, 2006h), for lower 5bits of the PPU status register (Port
2002h), and for upper 2bit of palette values (Port 2007h at PPU address
3F00h-3FFFh). That garbage value is:
1) The 8bit-value most recently written to any PPU port (2000h-2007h).
2) The 8bit-value most recently read from 2004h or 2007h,
3) The 3bit-value most recently read from 2002h (lower 5bit unchanged).
4) Zero if none of the above has "updated" the garbage for longer period.
Reading from Palette Memory
Palette entries are 6bit values, when reading from palette memory, the upper
two bits are garbage (see above). In monochrome mode (Port 2001h/Bit0=1) the
returned lower 4bit are zero. Also, palette reads appear a bit unstable, and
occasionally return incorrect values (at least on my PAL NES console).
Reading from empty Expansion / SRAM area at 4100h-7FFFh
Returns the most recently fetched data byte. That is: The third opcode byte
(direct 16bit addressing), or the second zero-page byte (indirect
addressing). In either case, the returned value is the MSB of 16bit BASE
address, regardless of any index value which may wrap the MSB to the next
page. For example: [4510h]=45h and [44FFh+11h]=44h are receiving different
values, even though both are reading from the same memory address.
Reading from empty Expansion / APU area at 4000h-40FFh
Empty bits and bytes are: Write-only APU Ports 4000h-4014h, unused expansion
addresses 4018h-40FFh, and unused bits in APU/Joypad Ports: 4015h/Bit5,
4016h/Bit7-5 (NES) or Bit7-3 (Famicom), and 4017h/Bit7-5. Normally returned
garbage is 40h (base MSB, as described for 4100h-7FFFh), unless when indexing
causes a page-wrap (from 3Fxxh+yyh to 40zzh), in that case several
"unpredictable" things are happening:
The CPU adds the index to the address LSB, and reads from that address
(3Fzzh) by mistake, in a second cycle the CPU adds the carry-out to the
address MSB, and tries to read from the correct address (40zzh). The hardware
doesn't output data for 40zzh, so that the CPU receives the most recently
fetched data byte, which has been [3Fzzh], which is a mirror of PPU register
[200zh]. To the worst, most PPU registers are either write-only, or cannot be
read during rendering, see PPU Garbage above.
Cleverly used, this allows to detect the number of unused bits in 4016h, and
to separate between NES or Famicom hardware.
| CPU 65XX Microprocessor |
Overview
CPU Registers and Flags
CPU Memory Addressing
Instruction Set
CPU Memory and Register Transfers
CPU Arithmetic/Logical Operations
CPU Rotate and Shift Instructions
CPU Jump and Control Instructions
CPU Illegal Opcodes
Other Info
CPU Assembler Directives
CPU The 65XX Family
CPU Local Usage
| CPU Registers and Flags |
The 65XX CPUs are equipped with not more than three 8bit general purpose
registers (A, X, Y). However, the limited number of registers (and
complete lack of 16bit registers other than PC) is parts of covered by
comfortable memory operations, especially page 0 of memory (address
0000h-00FFh) may be used for relative fast and complicated operations,
in so far one might say that the CPU has about 256 8bit 'registers' (or
128 16bit 'registers') in memory. For details see Memory Addressing
chapter.
Registers
Bits Name Expl. 8 A Accumulator 8 X Index Register X 8 Y Index Register Y 16 PC Program Counter 8 S Stack Pointer (see below) 8 P Processor Status Register (see below) |
Stack Pointer
The stack pointer is addressing 256 bytes in page 1 of memory, ie.
values 00h-FFh will address memory at 0100h-01FFh. As for most other
CPUs, the stack pointer is decrementing when storing data. However, in
the 65XX world, it points to the first FREE byte on stack, so, when
initializing stack to top set S=(1)FFh (rather than S=(2)00h).
Processor Status Register (Flags)
Bit Name Expl. 0 C Carry (0=No Carry, 1=Carry) 1 Z Zero (0=Nonzero, 1=Zero) 2 I IRQ Disable (0=IRQ Enable, 1=IRQ Disable) 3 D Decimal Mode (0=Normal, 1=BCD Mode for ADC/SBC opcodes) 4 B Break Flag (0=IRQ/NMI, 1=BRK/PHP opcode) 5 - Not used (Always 1) 6 V Overflow (0=No Overflow, 1=Overflow) 7 N Negative/Sign (0=Positive, 1=Negative) |
Carry Flag (C)
Caution: When used for subtractions (SBC and CMP), the carry flag is
having opposite meaning as for normal 80x86 and Z80 CPUs, ie. it is SET
when above-or-equal. For all other instructions (ADC, ASL, LSR, ROL,
ROR) it works as normal, whereas ROL/ROR are rotating <through> carry
(ie. much like 80x86 RCL/RCR and not like ROL/ROR).
Zero Flag (Z), Negative/Sign Flag (N), Overflow Flag (V)
Works just as everywhere, Z it is set when result (or destination
register, in case of some 'move' instructions) is zero, N is set when
signed (ie. same as Bit 7 of result/destination). V is set when an
addition/subtraction exceeded the maximum range for signed numbers
(-128..+127).
IRQ Disable Flag (I)
Disables IRQs when set. NMIs (non maskable interrupts) and BRK
instructions cannot be disabled.
Decimal Mode Flag (D)
Packed BCD mode (range 00h..99h) for ADC and SBC opcodes.
Break Flag (B)
The Break flag is intended to separate between IRQ and BRK which are both
using the same vector, [FFFEh]. The flag cannot be accessed directly, but
there are 4 situations which are writing the P register to stack, which
are then allowing the examine the B-bit in the pushed value: The BRK and
PHP opcodes always write "1" into the bit, IRQ/NMI execution always write
"0".
| CPU Memory Addressing |
XXX/???
On-Chip Bi-directional I/O port
Addresses (00)00h and (00)01h are occupied by an I/O port which is
built-in into 6510 and 8500 CPUs (eg. used in C64), be sure not to use the
addresses as normal memory. For description read chapter about I/O ports.
Caution
Because of the identical format, assemblers will be more or less unable
to separate between [XXh+r] and [00XXh+r], the assembler will most
likely produce [XXh+r] when address is already known to be located in
page 0, and [00XXh+r] in case of forward references.
Beside for different opcode size/time, [XXh+r] will always access page 0
memory (even when XXh+r>FFh), while [00XXh+r] may direct to memory in
page 0 or 1, to avoid unpredictable results be sure not to use
(00)XXh+r>FFh if possible.
| CPU Memory and Register Transfers |
Register to Register Transfer
A8 nz---- 2 TAY Transfer Accumulator to Y Y=A AA nz---- 2 TAX Transfer Accumulator to X X=A BA nz---- 2 TSX Transfer Stack pointer to X X=S 98 nz---- 2 TYA Transfer Y to Accumulator A=Y 8A nz---- 2 TXA Transfer X to Accumulator A=X 9A ------ 2 TXS Transfer X to Stack pointer S=X |
Load Register from Memory
A9 nn nz---- 2 LDA #nn Load A with Immediate A=nn A5 nn nz---- 3 LDA nn Load A with Zero Page A=[nn] B5 nn nz---- 4 LDA nn,X Load A with Zero Page,X A=[nn+X] AD nn nn nz---- 4 LDA nnnn Load A with Absolute A=[nnnn] BD nn nn nz---- 4* LDA nnnn,X Load A with Absolute,X A=[nnnn+X] B9 nn nn nz---- 4* LDA nnnn,Y Load A with Absolute,Y A=[nnnn+Y] A1 nn nz---- 6 LDA (nn,X) Load A with (Indirect,X) A=[WORD[nn+X]] B1 nn nz---- 5* LDA (nn),Y Load A with (Indirect),Y A=[WORD[nn]+Y] A2 nn nz---- 2 LDX #nn Load X with Immediate X=nn A6 nn nz---- 3 LDX nn Load X with Zero Page X=[nn] B6 nn nz---- 4 LDX nn,Y Load X with Zero Page,Y X=[nn+Y] AE nn nn nz---- 4 LDX nnnn Load X with Absolute X=[nnnn] BE nn nn nz---- 4* LDX nnnn,Y Load X with Absolute,Y X=[nnnn+Y] A0 nn nz---- 2 LDY #nn Load Y with Immediate Y=nn A4 nn nz---- 3 LDY nn Load Y with Zero Page Y=[nn] B4 nn nz---- 4 LDY nn,X Load Y with Zero Page,X Y=[nn+X] AC nn nn nz---- 4 LDY nnnn Load Y with Absolute Y=[nnnn] BC nn nn nz---- 4* LDY nnnn,X Load Y with Absolute,X Y=[nnnn+X] |
* Add one cycle if indexing crosses a page boundary.
Store Register in Memory
85 nn ------ 3 STA nn Store A in Zero Page [nn]=A 95 nn ------ 4 STA nn,X Store A in Zero Page,X [nn+X]=A 8D nn nn ------ 4 STA nnnn Store A in Absolute [nnnn]=A 9D nn nn ------ 5 STA nnnn,X Store A in Absolute,X [nnnn+X]=A 99 nn nn ------ 5 STA nnnn,Y Store A in Absolute,Y [nnnn+Y]=A 81 nn ------ 6 STA (nn,X) Store A in (Indirect,X) [[nn+x]]=A 91 nn ------ 6 STA (nn),Y Store A in (Indirect),Y [[nn]+y]=A 86 nn ------ 3 STX nn Store X in Zero Page [nn]=X 96 nn ------ 4 STX nn,Y Store X in Zero Page,Y [nn+Y]=X 8E nn nn ------ 4 STX nnnn Store X in Absolute [nnnn]=X 84 nn ------ 3 STY nn Store Y in Zero Page [nn]=Y 94 nn ------ 4 STY nn,X Store Y in Zero Page,X [nn+X]=Y 8C nn nn ------ 4 STY nnnn Store Y in Absolute [nnnn]=Y |
Push/Pull
48 ------ 3 PHA Push accumulator on stack [S]=A 08 ------ 3 PHP Push processor status on stack [S]=P 68 nz---- 4 PLA Pull accumulator from stack A=[S] 28 nzcidv 4 PLP Pull processor status from stack P=[S] |
Notes: PLA sets Z and N according to content of A. The B-flag and unused flags cannot be changed by PLP, these flags are always written as "1" by PHP.
| CPU Arithmetic/Logical Operations |
Add memory to accumulator with carry
69 nn nzc--v 2 ADC #nn Add Immediate A=A+C+nn 65 nn nzc--v 3 ADC nn Add Zero Page A=A+C+[nn] 75 nn nzc--v 4 ADC nn,X Add Zero Page,X A=A+C+[nn+X] 6D nn nn nzc--v 4 ADC nnnn Add Absolute A=A+C+[nnnn] 7D nn nn nzc--v 4* ADC nnnn,X Add Absolute,X A=A+C+[nnnn+X] 79 nn nn nzc--v 4* ADC nnnn,Y Add Absolute,Y A=A+C+[nnnn+Y] 61 nn nzc--v 6 ADC (nn,X) Add (Indirect,X) A=A+C+[[nn+X]] 71 nn nzc--v 5* ADC (nn),Y Add (Indirect),Y A=A+C+[[nn]+Y] |
* Add one cycle if indexing crosses a page boundary.
Subtract memory from accumulator with borrow
E9 nn nzc--v 2 SBC #nn Subtract Immediate A=A+C-1-nn E5 nn nzc--v 3 SBC nn Subtract Zero Page A=A+C-1-[nn] F5 nn nzc--v 4 SBC nn,X Subtract Zero Page,X A=A+C-1-[nn+X] ED nn nn nzc--v 4 SBC nnnn Subtract Absolute A=A+C-1-[nnnn] FD nn nn nzc--v 4* SBC nnnn,X Subtract Absolute,X A=A+C-1-[nnnn+X] F9 nn nn nzc--v 4* SBC nnnn,Y Subtract Absolute,Y A=A+C-1-[nnnn+Y] E1 nn nzc--v 6 SBC (nn,X) Subtract (Indirect,X) A=A+C-1-[[nn+X]] F1 nn nzc--v 5* SBC (nn),Y Subtract (Indirect),Y A=A+C-1-[[nn]+Y] |
* Add one cycle if indexing crosses a page boundary.
Note: Compared with normal 80x86 and Z80 CPUs, incoming and resulting
Carry Flag are reversed.
Logical AND memory with accumulator
29 nn nz---- 2 AND #nn AND Immediate A=A AND nn 25 nn nz---- 3 AND nn AND Zero Page A=A AND [nn] 35 nn nz---- 4 AND nn,X AND Zero Page,X A=A AND [nn+X] 2D nn nn nz---- 4 AND nnnn AND Absolute A=A AND [nnnn] 3D nn nn nz---- 4* AND nnnn,X AND Absolute,X A=A AND [nnnn+X] 39 nn nn nz---- 4* AND nnnn,Y AND Absolute,Y A=A AND [nnnn+Y] 21 nn nz---- 6 AND (nn,X) AND (Indirect,X) A=A AND [[nn+X]] 31 nn nz---- 5* AND (nn),Y AND (Indirect),Y A=A AND [[nn]+Y] |
* Add one cycle if indexing crosses a page boundary.
Exclusive-OR memory with accumulator
49 nn nz---- 2 EOR #nn XOR Immediate A=A XOR nn 45 nn nz---- 3 EOR nn XOR Zero Page A=A XOR [nn] 55 nn nz---- 4 EOR nn,X XOR Zero Page,X A=A XOR [nn+X] 4D nn nn nz---- 4 EOR nnnn XOR Absolute A=A XOR [nnnn] 5D nn nn nz---- 4* EOR nnnn,X XOR Absolute,X A=A XOR [nnnn+X] 59 nn nn nz---- 4* EOR nnnn,Y XOR Absolute,Y A=A XOR [nnnn+Y] 41 nn nz---- 6 EOR (nn,X) XOR (Indirect,X) A=A XOR [[nn+X]] 51 nn nz---- 5* EOR (nn),Y XOR (Indirect),Y A=A XOR [[nn]+Y] |
* Add one cycle if indexing crosses a page boundary.
Logical OR memory with accumulator
09 nn nz---- 2 ORA #nn OR Immediate A=A OR nn 05 nn nz---- 3 ORA nn OR Zero Page A=A OR [nn] 15 nn nz---- 4 ORA nn,X OR Zero Page,X A=A OR [nn+X] 0D nn nn nz---- 4 ORA nnnn OR Absolute A=A OR [nnnn] 1D nn nn nz---- 4* ORA nnnn,X OR Absolute,X A=A OR [nnnn+X] 19 nn nn nz---- 4* ORA nnnn,Y OR Absolute,Y A=A OR [nnnn+Y] 01 nn nz---- 6 ORA (nn,X) OR (Indirect,X) A=A OR [[nn+X]] 11 nn nz---- 5* ORA (nn),Y OR (Indirect),Y A=A OR [[nn]+Y] |
* Add one cycle if indexing crosses a page boundary.
Compare
C9 nn nzc--- 2 CMP #nn Compare A with Immediate A-nn C5 nn nzc--- 3 CMP nn Compare A with Zero Page A-[nn] D5 nn nzc--- 4 CMP nn,X Compare A with Zero Page,X A-[nn+X] CD nn nn nzc--- 4 CMP nnnn Compare A with Absolute A-[nnnn] DD nn nn nzc--- 4* CMP nnnn,X Compare A with Absolute,X A-[nnnn+X] D9 nn nn nzc--- 4* CMP nnnn,Y Compare A with Absolute,Y A-[nnnn+Y] C1 nn nzc--- 6 CMP (nn,X) Compare A with (Indirect,X) A-[[nn+X]] D1 nn nzc--- 5* CMP (nn),Y Compare A with (Indirect),Y A-[[nn]+Y] E0 nn nzc--- 2 CPX #nn Compare X with Immediate X-nn E4 nn nzc--- 3 CPX nn Compare X with Zero Page X-[nn] EC nn nn nzc--- 4 CPX nnnn Compare X with Absolute X-[nnnn] C0 nn nzc--- 2 CPY #nn Compare Y with Immediate Y-nn C4 nn nzc--- 3 CPY nn Compare Y with Zero Page Y-[nn] CC nn nn nzc--- 4 CPY nnnn Compare Y with Absolute Y-[nnnn] |
* Add one cycle if indexing crosses a page boundary.
Note: Compared with normal 80x86 and Z80 CPUs, resulting Carry Flag is
reversed.
Bit Test
24 nn xz---x 3 BIT nn Bit Test A AND [nn], N=[nn].7, V=[nn].6 2C nn nn xz---x 4 BIT nnnn Bit Test A AND [..], N=[..].7, V=[..].6 |
Increment by one
E6 nn nz---- 5 INC nn Increment Zero Page [nn]=[nn]+1 F6 nn nz---- 6 INC nn,X Increment Zero Page,X [nn+X]=[nn+X]+1 EE nn nn nz---- 6 INC nnnn Increment Absolute [nnnn]=[nnnn]+1 FE nn nn nz---- 7 INC nnnn,X Increment Absolute,X [nnnn+X]=[nnnn+X]+1 E8 nz---- 2 INX Increment X X=X+1 C8 nz---- 2 INY Increment Y Y=Y+1 |
Decrement by one
C6 nn nz---- 5 DEC nn Decrement Zero Page [nn]=[nn]-1 D6 nn nz---- 6 DEC nn,X Decrement Zero Page,X [nn+X]=[nn+X]-1 CE nn nn nz---- 6 DEC nnnn Decrement Absolute [nnnn]=[nnnn]-1 DE nn nn nz---- 7 DEC nnnn,X Decrement Absolute,X [nnnn+X]=[nnnn+X]-1 CA nz---- 2 DEX Decrement X X=X-1 88 nz---- 2 DEY Decrement Y Y=Y-1 |
| CPU Rotate and Shift Instructions |
Shift Left
0A nzc--- 2 ASL A Shift Left Accumulator SHL A 06 nn nzc--- 5 ASL nn Shift Left Zero Page SHL [nn] 16 nn nzc--- 6 ASL nn,X Shift Left Zero Page,X SHL [nn+X] 0E nn nn nzc--- 6 ASL nnnn Shift Left Absolute SHL [nnnn] 1E nn nn nzc--- 7 ASL nnnn,X Shift Left Absolute,X SHL [nnnn+X] |
Shift Right
4A 0zc--- 2 LSR A Shift Right Accumulator SHR A 46 nn 0zc--- 5 LSR nn Shift Right Zero Page SHR [nn] 56 nn 0zc--- 6 LSR nn,X Shift Right Zero Page,X SHR [nn+X] 4E nn nn 0zc--- 6 LSR nnnn Shift Right Absolute SHR [nnnn] 5E nn nn 0zc--- 7 LSR nnnn,X Shift Right Absolute,X SHR [nnnn+X] |
Rotate Left through Carry
2A nzc--- 2 ROL A Rotate Left Accumulator RCL A 26 nn nzc--- 5 ROL nn Rotate Left Zero Page RCL [nn] 36 nn nzc--- 6 ROL nn,X Rotate Left Zero Page,X RCL [nn+X] 2E nn nn nzc--- 6 ROL nnnn Rotate Left Absolute RCL [nnnn] 3E nn nn nzc--- 7 ROL nnnn,X Rotate Left Absolute,X RCL [nnnn+X] |
Rotate Right through Carry
6A nzc--- 2 ROR A Rotate Right Accumulator RCR A 66 nn nzc--- 5 ROR nn Rotate Right Zero Page RCR [nn] 76 nn nzc--- 6 ROR nn,X Rotate Right Zero Page,X RCR [nn+X] 6E nn nn nzc--- 6 ROR nnnn Rotate Right Absolute RCR [nnnn] 7E nn nn nzc--- 7 ROR nnnn,X Rotate Right Absolute,X RCR [nnnn+X] |
Notes:
ROR instruction is available on MCS650X microprocessors after June, 1976.
ROL and ROL rotate an 8bit value through carry (rotates 9bits in total).
| CPU Jump and Control Instructions |
Normal Jumps
4C nn nn ------ 3 JMP nnnn Jump Absolute PC=nnnn 6C nn nn ------ 5 JMP (nnnn) Jump Indirect PC=WORD[nnnn] 20 nn nn ------ 6 JSR nnnn Jump and Save Return Addr. [S]=PC+2,PC=nnnn 40 nzcidv 6 RTI Return from BRK/IRQ/NMI P=[S], PC=[S] 60 ------ 6 RTS Return from Subroutine PC=[S]+1 |
Note: RTI cannot modify the B-Flag or the unused flag.
Glitch: For JMP [nnnn] the operand word cannot cross page boundaries, ie.
JMP [03FFh] would fetch the MSB from [0300h] instead of [0400h]. Very
simple workaround would be to place a ALIGN 2 before the data word.
Conditional Branches
10 dd ------ 2** BPL disp Branch on result plus if N=0 PC=PC+/-nn 30 dd ------ 2** BMI disp Branch on result minus if N=1 PC=PC+/-nn 50 dd ------ 2** BVC disp Branch on overflow clear if V=0 PC=PC+/-nn 70 dd ------ 2** BVS disp Branch on overflow set if V=1 PC=PC+/-nn 90 dd ------ 2** BCC disp Branch on carry clear if C=0 PC=PC+/-nn B0 dd ------ 2** BCS disp Branch on carry set if C=1 PC=PC+/-nn D0 dd ------ 2** BNE disp Branch on result not zero if Z=0 PC=PC+/-nn F0 dd ------ 2** BEQ disp Branch on result zero if Z=1 PC=PC+/-nn |
** The execution time is 2 cycles if the condition is false (no branch executed). Otherwise, 3 cycles if the destination is in the same memory page, or 4 cycles if it crosses a page boundary (see below for exact info).
Note: After subtractions (SBC or CMP) carry=set indicates
above-or-equal, unlike as for 80x86 and Z80 CPUs. Obviously, this still
applies even when using 80XX-style syntax.
Interrupts, Exceptions, Breakpoints
00 ---1-- 7 BRK Force Break B=1 [S]=PC+1,[S]=P,I=1,PC=[FFFE] -- ---1-- ?? /IRQ Interrupt B=0 [S]=PC,[S]=P,I=1,PC=[FFFE] -- ---1-- ?? /NMI NMI B=0 [S]=PC,[S]=P,I=1,PC=[FFFA] -- ---1-- T+6 /RESET Reset PC=[FFFC],I=1 |
Notes: IRQs can be disabled by setting the I-flag, a BRK command, a NMI, and a /RESET signal cannot be masked by setting I.
BRK/IRQ/NMI first change the B-flag, then write P to stack, and then set
the I-flag, the D-flag is NOT changed and should be cleared by software.
The same vector is shared for BRK and IRQ, software can separate between
BRK and IRQ by examining the pushed B-flag only.
The RTI opcode can be used to return from BRK/IRQ/NMI, note that using the
return address from BRK skips one dummy/parameter byte following after the
BRK opcode.
Software or hardware must take care to acknowledge or reset /IRQ or /NMI
signals after processing it.
IRQs are executed whenever "/IRQ=LOW AND I=0". NMIs are executed whenever "/NMI changes from HIGH to LOW". |
If /IRQ is kept LOW then same (old) interrupt is executed again as soon as setting I=0. If /NMI is kept LOW then no further NMIs can be executed.
CPU Control
18 --0--- 2 CLC Clear carry flag C=0 58 ---0-- 2 CLI Clear interrupt disable bit I=0 D8 ----0- 2 CLD Clear decimal mode D=0 B8 -----0 2 CLV Clear overflow flag V=0 38 --1--- 2 SEC Set carry flag C=1 78 ---1-- 2 SEI Set interrupt disable bit I=1 F8 ----1- 2 SED Set decimal mode D=1 |
No Operation
EA ------ 2 NOP No operation No operation |
Conditional Branch Page Crossing
The branch opcode with parameter takes up two bytes, causing the PC to get
incremented twice (PC=PC+2), without any extra boundary cycle. The signed
parameter is then added to the PC (PC+disp), the extra clock cycle occurs
if the addition crosses a page boundary (next or previous 100h-page).
| CPU Illegal Opcodes |
SAX and LAX
87 nn ------ 3 SAX nn STA+STX [nn]=A AND X 97 nn ------ 4 SAX nn,Y STA+STX [nn+Y]=A AND X 8F nn nn ------ 4 SAX nnnn STA+STX [nnnn]=A AND X 83 nn ------ 6 SAX (nn,X) STA+STX [WORD[nn+X]]=A AND X A7 nn nz---- 3 LAX nn LDA+LDX A,X=[nn] B7 nn nz---- 4 LAX nn,Y LDA+LDX A,X=[nn+Y] AF nn nn nz---- 4 LAX nnnn LDA+LDX A,X=[nnnn] BF nn nn nz---- 4* LAX nnnn,X LDA+LDX A,X=[nnnn+X] A3 nn nz---- 6 LAX (nn,X) LDA+LDX A,X=[WORD[nn+X]] B3 nn nz---- 5* LAX (nn),Y LDA+LDX A,X=[WORD[nn]+Y] |
For SAX, both A and X are output to databus, LOW-bits are stronger than HIGH-bits, resulting in a "forceful" AND operation.
For LAX, the same value is written to both A and X.
Combined ALU-Opcodes
Opcode high-bits, flags, commands:
00+yy nzc--- SLO op ASL+ORA op=op SHL 1 // A=A OR op 20+yy nzc--- RLA op ROL+AND op=op RCL 1 // A=A AND op 40+yy nzc--- SRE op LSR+EOR op=op SHR 1 // A=A XOR op 60+yy nzc--v RRA op ROR+ADC op=op RCR 1 // A=A ADC op C0+yy nzc--- DCP op DEC+CMP op=op-1 // A-op E0+yy nzc--v ISC op INC+SBC op=op+1 // A=A-op cy? |
Opcode low-bits, clock cycles, operands:
07+xx nn 5 nn [nn] 17+xx nn 6 nn,X [nn+X] 03+xx nn 8 (nn,X) [WORD[nn+X]] 13+xx nn 8 (nn),Y [WORD[nn]+Y] 0F+xx nn nn 6 nnnn [nnnn] 1F+xx nn nn 7 nnnn,X [nnnn+X] 1B+xx nn nn 7 nnnn,Y [nnnn+Y] |
Other Illegal Opcodes
0B nn nzc--- 2 ANC #nn AND+ASL A=A AND nn 2B nn nzc--- 2 ANC #nn AND+ROL A=A AND nn 4B nn nzc--- 2 ALR #nn AND+LSR A=(A AND nn)*2 MUL2??? 6B nn nzc--v 2 ARR #nn AND+ROR A=(A AND nn)/2 8B nn nz---- 2 XAA #nn ((2)) TXA+AND A=X AND nn AB nn nz---- 2 LAX #nn ((2)) LDA+TAX A,X=nn CB nn nzc--- 2 AXS #nn CMP+DEX X=A AND X -nn cy? EB nn nzc--v 2 SBC #nn SBC+NOP A=A-nn cy? 93 nn ------ 6 AHX (nn),Y ((1)) [WORD[nn]+Y] = A AND X AND H 9F nn nn ------ 5 AHX nnnn,Y ((1)) [nnnn+Y] = A AND X AND H 9C nn nn ------ 5 SHY nnnn,X ((1)) [nnnn+X] = Y AND H 9E nn nn ------ 5 SHX nnnn,Y ((1)) [nnnn+Y] = X AND H 9B nn nn ------ 5 TAS nnnn,Y ((1)) STA+TXS S=A AND X // [nnnn+Y]=S AND H BB nn nn nz---- 4* LAS nnnn,Y LDA+TSX A,X,S = [nnnn+Y] AND S |
NUL/NOP and KIL/JAM/HLT
xx ------ 2 NOP (xx=1A,3A,5A,7A,DA,FA) xx nn ------ 2 NOP #nn (xx=80,82,89,C2,E2) xx nn ------ 3 NOP nn (xx=04,44,64) xx nn ------ 4 NOP nn,X (xx=14,34,54,74,D4,F4) xx nn nn ------ 4 NOP nnnn (xx=0C) xx nn nn ------ 4* NOP nnnn,X (xx=1C,3C,5C,7C,DC,FC) xx ------ - KIL (xx=02,12,22,32,42,52,62,72,92,B2,D2,F2) |
NOP doesn't change any registers or flags, the operand (if any) is fetched, may be useful for delays, patches, or for read-sensitive I/O ports. KIL halts the CPU, the data bus will be set to #$FF, KIL can be suspended by /RESET signal (not sure if also by /IRQ or /NMI ???).
note to ANC: this command performs an AND operation only, but bit 7 is put
into the carry, as if the ASL/ROL would have been executed.
note to ARR: part of this command are some ADC mechanisms. following effects
appear after AND but before ROR: the V-Flag is set according to
(A and #{imm})+#{imm}, bit 0 does NOT go into carry, but bit 7 is exchanged
with the carry.
note to XAA: DO NOT USE!!! Highly unstable!!!
note to LAX: DO NOT USE!!! On my C128, this opcode is stable, but on my C64-II
it loses bits so that the operation looks like this: ORA #? AND #{imm} TAX.
note to AXS: performs CMP and DEX at the same time, so that the MINUS sets
the flag like CMP, not SBC.
Combinations of STA/STX/STY:
AHX {adr} = stores A&X&H into {adr}
SHX {adr} = stores X&H into {adr}
SHY {adr} = stores Y&H into {adr}
|
note: sometimes the &H drops off. Also page boundary crossing will not work as
expected (the bank where the value is stored may be equal to the value stored).
| CPU Assembler Directives |
Below are some common 65XX assembler directives, and the corresponding
expressions in 80XX-style language.
65XX-style 80XX-style Expl. *=$c100 org 0c100h sets the assumed origin in memory *=*+8 org $+8 increments origin, does NOT produce data label label: sets a label equal to the current address label=$dc00 label equ 0dc00h assigns a value or address to label .by $00 db 00h defines a (list of) byte(s) in memory .byt $00 defb 00h same as .by and db .wd $0000 dw 0000h defines a (list of) word(s) in memory .end end indicates end of source code file |nn [|nn] force 16bit "00NN" instead 8bit "NN" #<nnnn nnnn AND 0FFh isolate lower 8bits of 16bit value #>nnnn nnnn DIV 100h isolate upper 8bits of 16bit value |
| CPU The 65XX Family |
Different versions of the 6502:
All of these processors are the same concerning the software-side:
6501 6502 Used in the CBM floppies and some other 8 bit computers. 6507 Used in Atari 2600, 28pins (only 13 address lines, no /IRQ, no /NMI). 6510 Used in C64, with one built-in I/O port. 8500 Used in C64-II, with different pin-outs. 8502 Used in C128s. |
Some processors of the family which are not 100% compatible:
65C02 Extension of the 6502, used in the C16, C116 and the Plus/4 computers. 65SC02 Small version of the 65C02 which lost a few opcodes again. 65CE02 Extension of the 65C02, used in the C65. 65816 Extended 6502 with new opcodes and 16 bit operation modes. 2A03 Nintendo NES/Famicom, modified CPU, built-in sound/video registers. |
| CPU Local Usage |
CPU
The NES uses a customized NMOS 6502 CPU, engineered and produced by Ricoh.
It's primary customization adds audio. Audio registers are mapped internal
to the CPU; all waveform generation is done internal to the CPU as well.
The NES's 6502 does not contain support for decimal mode. Both the CLD and
SED opcodes function normally, but the 'd' bit of P is unused in both ADC
and SBC. It is common practice for games to CLD prior to code execution,
as the status of 'd' is unknown on power-on and on reset.
NMIs may be generated by PPU each VBlank.
IRQs may be generated by APU and by external hardware.
The CPU does include undocumented opcodes, just like normal 6502 CPUs.
The NTSC NES runs at 1.7897725MHz, and 1.773447MHz for PAL. Which is pretty
fast for a 6502 compatible CPU, for example C64 used only 1MHz, and Atari
2600 only 1.2MHz.
| Hardware Pin-Outs |
Pin-Outs
Cartridge Pin-Outs
Controllers - Pin-Outs
Chipset Pin-Outs
NES Expansion Port
Upgrading
Nocash SRAM Circuit
| Chipset Pin-Outs |
2A03 Pin-Outs & Signal Description (CPU and APU)
Pin Name Dir Expl.
1 ROUT Out Sound channel 1+2 output
2 COUT Out Sound channel 3+4+5 output
3 /RES In Resets several internal 2A03 registers, and the 6502.
4-19 A0-15 Out Address Bus
20 GND - Supply Ground
21-28 D7-0 I/O Data Bus
29 CLK In Master clock input (236,250/11 MHz), clocks an internal
divide-by-12 counter.
30 ? In Normally grounded in NES/FC consoles, this pin has unknown
functionality. I suspect that it is an input controlling
somthing, since the pin does draw a little current.
31 PHI2 Out Divide-by-12 result of the CLK signal (1.79 MHz).
The internal 6502 along with function generating hardware,
is clocked off this frequency, and is available externally
here so that it can be used as a data bus enable signal
(when at logic level 1) for external 6502 address decoder
logic. The signal has a 62.5% duty cycle.
32 /IRQ In Interrupt Request (Low)
33 /NMI In Non-Maskable Interrupt (on High-to-Low Transition)
34 R/W Out Direction of 6502's data bus (0=Write/Out, 1=Read/In)
35 /JOY2 Out Low if A0-A15=4017h, R/W=0, PHI2=1
36 /JOY1 Out Low if A0-A15=4016h, R/W=0, PHI2=1
37-39 J2-0 Out Bit2-0 of internal register 4016h (Bit0 = Joystick strobe)
40 VCC - Supply +5VDC
|
2C02 Pin-Outs & Signal Descriptions (PPU)
Pin Dir Name Expl 1 In CPU R/W Direction when /CS=LOW 2-9 I/O CPU D0-D7 Data when /CS=LOW 10-12 In CPU A2-A0 Register Select when /CS=LOW 13 In CPU /CS CPU read/write to/from PPU Registers 14-17 I/O EXT0-EXT3 External Master/Slave Video signal (not used) 18 In CLK 21.47727MHz NTSC, 26.601712MHz PAL 19 Out /VBL VBlank, LOW max 20 scanlines or until acknowledged 20 In VEE GND Supply Ground 21 Out VOUT Composite Video output 22 In /SYNC EXT External Master /VBL for use by slave (not used) (*) 23,24 Out PPU /W,/R Video memory Write/Read requests 25-30 Out PPU A13-A8 Video memory MSB-address lines 31-38 I/O PPU AD7-AD0 Video memory LSB-address and data lines 39 Out PPU ALE Address Latch Enable, HIGH when A0-A7 output at AD0-AD7 40 In VCC +5VDC Supply |
(*) On Famicom consoles, /SYNC is always tied to logical one. On the NES however, this pin is tied in with the 2A03's reset input, and as a result, the picture is always disabled while the reset switch is held in on an NES.
| NES Expansion Port |
NES Expansion Port, 48-pins, (at bottom of console, rarely used)
Pin Dir Expl. 1,48,2,47 Out VCC,VCC,GND,GND (Supply +5VDC and Ground) 23 Out VDD voltage from external power supply (usually +10VDC) 3 In AIN (Audio Input) 21,22,23,24 Out VOUT, AOUT (Video and Audio Outputs) 4,14,25-32 I/O CPU /NMI,/IRQ,D7,D6,D5,D4,D3,D2,D1,D0 5,24 Out CPU A15, CIC 4MHz 6-10,38-42 I/O Cart Pin 51-55,20-16 43,44,45 Out OUT0, OUT1, OUT2 (Port 4016h Bit0-2 Outputs) 34 and 37 Out PORT0-CLK (both pins) (CPU Read from Port 4016h) 11 and 17 Out PORT1-CLK (both pins) (CPU Read from Port 4017h) 35,12,33,13,36 In PORT0-0,1,2,3,4 (Port 4016h Bit0-3 Inverted Inputs) 19,20,15,16,18 In PORT1-0,1,2,3,4 (Port 4017h Bit0-3 Inverted Inputs) 46 - Unused |
| Nocash SRAM Circuit |
Step 1 - Basic Connection, NROM support (32K+8K), Horizontal Mirroring
________ ________ ________
VCC ---------|A13-A19 | VCC ------tmp-|A15-A18 | VCC -----tmp-|A13-A18 |
CPU A0-A12 --|A0-A12 | CPU A0-A14 ---|A0-A14 | PPU A0-A12 --|A0-A12 |
CPU D0-D7 ---|D0-D7 | CPU D0-D7 ----|D0-D7 | PPU D0-D7 ---|D0-D7 |
CPU /PRG ----|/CS | CPU /PRG -----|/CS | PPU A13 -tmp-|/CS |
LPT /LF -tmp-|/OE BIOS| LPT /SEL -----|/OE WRAM| PPU /R ------|/OE VRAM|
|________| CPU R/W ------|/WE | PPU /W ------|/WE |
___ |________| |________|
VCC -|___|- CPU /RESET
CIC /RESET --cut-- CPU /RESET FLOPPY 5VDC ------- VCC (supply)
CIC /RESET --|<|-- CPU /RESET LPT GND ------- GND
LPT /INIT --|<|-- CPU /RESET PPU /A13 --tmp-- NES /VCS
LPT /STROBE --|<|-- CPU /NMI PPU A10 --tmp-- NES VA10
CIC MODE --cut-- VCC (lockout) LPT BUSY ------- CPU OUT2
CIC MODE ------- GND (no lockout) LPT D7 ------- EXP PORT0-1
|
At this stage, the console won't work if an external cartridge is inserted.
Step 2 - Horizontal or Vertical Mirroring Control
____ ____ LPT D0 ----|OR \__|AND |_______ NES VA10 (out) PPU A10 --undo-- NES VA10 PPU A10 ---|____/ |7411| LPT D1 ----|OR \__| |__tmp__ VCC (third AND-input, used in Step 3) PPU A11 ---|____/ |____| |
Step 3 - Internal Circuit Disable (Required for Internal Circuit only)
____ ____ ___ CPU /PRG --|OR \__ SLOT /PRG LPT /LF --|AND \__ CART VCC -|___|- LPT /LF /CART -----|____/ LPT /SEL -|____/ VCC -|___|- LPT /SEL PPU /R ----|OR \__ SLOT /R CART -----|NAND\__ /CART VCC -|___|- LPT D0 /CART -----|____/ CART -----|____/ VCC -|___|- LPT D1 CART ------|OR \__ VRAM /CS CPU A14 --|AND \__ SLOT A14 PPU A13 ---|____/ CART -----|____/ NES /VCS --cut-- SLOT /VCS /CART -----|OR \__ AND (Step 2) NES VA10 --cut-- SLOT VA10 SLOT VA10 -|____/ CPU A14 --cut-- SLOT A14 CART ------|OR \__ ____ CPU /PRG --cut-- SLOT /PRG PPU /A13 --|____/ |AND \__ NES /VCS PPU /R --cut-- SLOT /R SLOT /VCS -|OR \__|____/ VCC --undo-- AND (Step 2) /CART -----|____/ PPU A13 -undo- VRAM /CS PPU /A13 --undo- NES /VCS |
Also allows to disable the internal circuit so that external cartridges can be
used when LPT cable is disconnected (or when LPT signals are all HIGH).
Step 4 - UNROM (N*16K+8K) and CNROM (32K+N*8K) Bank Switching
__________ __________ ____
LPT /LF ----|/CLKEN1 | LPT LF -----|/CLKEN1 | WRAM A14 --|____|-- VCC
CPU R/W ----|/CLKEN2 | CPU R/W ----|/CLKEN2 | WRAM A15 --|____|-- VCC
CPU /PRG ---|CLK | CPU /PRG ---|CLK | WRAM A16 --|____|-- VCC
CPU D0..3 --|Q0..3 | CPU D0..3 --|Q0..3 | LPT /LF ---|NAND\_ LPT LF
GND --------|/OE1 | CPU A14 ----|/OE1 | LPT /LF ---|____/
GND --------|/OE2 74173| GND --------|/OE2 74173| LPT /SEL --|NAND\_ BIOS
GND --------|RST CNROM| GND --------|RST UNROM| LPT LF ----|____/ /OE
VRAM A13-16-|D0..3 | WRAM A14-16-|D0..2 | WRAM A15-A16 --undo-- VCC
|__________| |__________| VRAM A13-A16 --undo-- VCC
LPT /LF --undo-- BIOS /OE WRAM A14 --undo-- CPU A14
|
Step 5 - Optional 8bit high-speed upload connection
____ ____ __________ CPU A13 --|AND | CPU /PRG -|AND | ____ CPU D0-7--|Q0-7 D0-7|--LPT D0-7 CPU A14 --|7411| CPU R/W --|7411| VCC-|NAND\__________|/OE1 /OE2|--LPT /SEL CPU PHI2 -|____|-----------|____|-----|____/ 74541 |__________| |
The 1bit PORT0-1 connection is no longer used (may be disconnected if desired).
Compatibility Notes
WRAM and VRAM are not write-protected, and may get overwritten by accidental
writes to ROM/VROM area, that applies also for writes to bank selection ports
(no problem for cartridges that handle bus-conflicts, it will simply replace
the value in RAM by the (same) written value). In NROM mode, bank selection
ports are not protected against accidental ROM-area writes.
Soldering Notes
To reduce the amount of wires, the WRAM/VRAM chips can be stacked on top of
the internal 2K SRAMs with 1:1 connection for most pins, also the BIOS EPROM
socket can be stacked on the WRAM chip.
Optionally, the circuit could be connected externally to the cartridge slot
(with /RESET and /NMI connected to unused cartridge/expansion port pins),
the /CART and CART signals would be not required, Step 3 could be left out.
Parts List
2 SRAM WRAM/VRAM, min 32K/8K, recommended 128K/32K, max 128K/128K 1 EPROM BIOS, 27C64 or similar, min 8K 2 74LS32 quad 2-input OR gates 1 74LS08 quad 2-input AND gates 1 74LS00 quad 2-input NAND gates 1 74LS11 triple 3-input AND gates 2 74LS173 4-bit 3-state flip-flops 1 74LS541 8-bit 3-state buffer/line driver 8 10K pull-up resitors 3 1N4148 diodes for /RESET and /NMI |
Plus, eprom socket, optionally also sockets for all other chips, 100nF
capacitors for power supply of all chips, centronics printer cable, centronics
socket, wire, board, solder, eprom burner, etc.
BIOS ROM-Image
0000 85 04 48 8A 48 A9 19 8D FA FF A9 04 8D FB FF A2 0010 08 E0 00 D0 FC 68 AA 68 60 A9 00 06 04 69 03 8D 0020 16 40 CA 40 8A 48 A9 3B 8D FA FF A9 04 8D FB FF 0030 A2 08 E0 00 D0 FC 68 AA A5 04 60 24 0D 30 09 AD 0040 16 40 4A 4A 26 04 CA 40 AD 00 60 85 04 A2 00 40 0050 20 24 04 A2 7E A0 04 24 0D 30 04 A2 8D A0 04 8E 0060 FA FF 8C FB FF 8D FF FF A9 00 8D 01 20 8D 06 20 0070 8D 06 20 A2 00 A0 20 A9 01 85 04 4C 7B 04 AD 00 0080 60 8D 07 20 CA D0 FE 88 D0 FE 4C 1C 06 AD 16 40 0090 4A 4A 26 04 90 FE A5 04 8D 07 20 A9 01 85 04 CA 00A0 D0 FE 88 D0 FE 4C 1C 06 20 24 04 A2 DC A0 04 24 00B0 0D 30 04 A2 EE A0 04 8E FA FF 8C FB FF 8D FF FF 00C0 A0 BF A2 FF C9 FF D0 04 A0 FF A2 F9 8C FC 04 8C 00D0 E2 04 E8 A0 40 A9 01 85 04 4C D9 04 AD 00 60 CA 00E0 9D 00 FF D0 FE CE E2 04 88 D0 FE 4C 1C 06 AD 16 00F0 40 4A 4A 26 04 90 FE A5 04 CA 9D 00 FF A9 01 85 0100 04 E0 00 D0 FE CE FC 04 88 D0 FE 4C 1C 06 A2 00 0110 20 24 04 95 05 E8 E0 08 D0 F6 A2 00 B5 05 9D FA 0120 FF E8 E0 06 D0 F6 A1 05 81 05 4C 2A 05 A2 55 A0 0130 AA 8E FE FF 8C FF FF EC FE FF D0 F5 CC FF FF D0 0140 F0 8C FE FF 8E FF FF CC FE FF D0 E5 EC FF FF D0 0150 E0 60 A2 00 BD 61 05 20 00 04 E8 BD 61 05 D0 F4 0160 60 4E 4F 24 4E 45 53 20 42 49 4F 53 20 56 31 2E 0170 30 00 A9 00 85 0D 20 87 05 A9 80 85 0D 20 87 05 0180 F0 04 A9 00 85 0D 60 A2 00 A0 2B 20 24 04 DD A1 0190 05 F0 02 A0 2D E8 E0 08 D0 F1 98 20 00 04 C9 2B 01A0 60 00 FF 55 AA 0F F0 3C C3 A9 57 20 00 04 A2 FF 01B0 8D FF FF E8 8E 00 80 8E FF BF EC FF FF F0 06 E0 01C0 1F D0 F0 A2 01 E8 8A 20 00 04 60 A9 56 20 00 04 01D0 A2 40 A0 56 A9 00 8D 01 20 CA 8E FF FF 8D 06 20 01E0 8D 06 20 8C 07 20 8E 07 20 D0 EE A2 00 8E FF FF 01F0 8D 06 20 8D 06 20 CD 07 20 CC 07 20 D0 0A EC 07 0200 20 D0 05 E8 E0 40 D0 E5 8A 20 00 04 60 20 2D 05 0210 20 52 05 20 72 05 20 A9 05 20 CB 05 A9 52 20 00 0220 04 20 24 04 C9 57 D0 03 4C A8 04 C9 56 D0 03 4C 0230 50 04 C9 46 D0 03 4C 0E 05 4C 39 06 A2 00 BD 00 0240 E0 9D 00 04 BD 00 E1 9D 00 05 BD 00 E2 9D 00 06 0250 BD 00 E3 9D 00 07 E8 D0 E5 60 78 D8 A9 00 8D 00 0260 20 AD 02 20 A2 FF 9A 20 3C E2 4C 0D 06 FF FF FF 0270 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF .... FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 1FF0 FF FF FF FF FF FF FF FF FF FF 00 00 5A E2 00 00 |
To be copied to the highest memory location, ie. E000h-FFFFh for a 64K EPROM.
| About Everynes |
Everynes
Everything about NES and Famicom.
Nocash Technical Specifications written 2004 by Martin Korth.
Everynes Text and Html and Debugger versions and updates available at:
http://nocash.emubase.de/nes.htm |
I've originally written Everynes when collecting and sorting-out relevant info for making the no$nes emulator/debugger. I've included a copy of the resulting document in the debuggers help text, and also released raw txt/htm versions, which may be eventually of some use to NES/Famicom programmers.
Help welcome
Please let me know if you come across anything that is incomplete, incorrect,
or unclear. A couple of details (marked by question marks) are definetly
unclear to me - additional info would be very welcome!
My email address hides in no$nes.exe about box (for anti-spam reasons).
Thanks & Credits
Most of the Everynes document is based on information from many other
documents found at nesdev.parodius.com - hoping that nobody gets angry about
picking info from his/her docs - I'd like to send many thanks to the authors
of that great documents, and to all people whom have contributed information
to those docs, complete list as far as known to me - many thangs to:
MAPPERS.NFO
Comprehensive NES Mapper Document v0.80 by \Firebug\
Thanks to FanWen, Y0SHi, D, Jim Geffre, Goroh, Paul Robson, Mark Knibbs.
2A03TECH.TXT
2A03 technical reference by Brad Taylor
Thanks to Matthew Conte, Kentaro Ishihara, Goroh, Memblers, FluBBa, Izumi,
Chibi-Tech, Quietust, SnowBro, Bananmos, Kevin Horton, and many others for
their time and help on and off the NESdev mailing list, and the Membled
Messageboards.
2C02TECH.TXT
NTSC 2C02 technical reference by Brad Taylor
Thanks to the NES community. http://nesdev.parodius.com.
Special thanks to Neal Tew for scrolling information.
NESTECH2.TXT
Nintendo Entertainment System Documentation, Version: 2.00
Alex Krasivsky
Andrew Davie
Avatar Z
Barubary
Bluefoot
CiXeL
Chi-Wen Yang
Chris Hickman
D
Dan Boris
David de Regt
Donald Moore
Fredrik Olsson
Icer Addis
Jon Merkel
Kevin Horton
Loopy
Marat Fayzullin
Mark Knibbs
Martin Nielsen
Matt Conte
Matthew Richey
Memblers
MiKael Iushin
Mike Perry
Morgan Johansson
Neill Corlett
Pat Mccomack
Patrik Alexandersson
Paul Robson
Ryan Auge
Stumble
Tennessee Carmel-Veilleux
Thomas Steen
Tony Young
Vince Indriolo
\FireBug\
FFPA.TXT
Famicom Four-Player Adapters Technical Document by Richard Hoelscher
NES4PLAY.TXT
NES 4player-adapter documentation by Fredrik Olsson
Special thanks to:
Juan Antonio Gomez Galvarez
Yoshi
Marat Fayzulin
Morgan Johansson
Pin-Outs
drk421
Siudym'2001
6205BUGS.TXT
Ivo van Poorten
NLOCKOUT.TXT
by Mark (Knipps?)
VSDOC.TXT
VS Unisystem information version 1.0, by Fx3
PC10DOC.TXT
Nintendo Playchoice 10 Hardware Description by Oliver Achten
NESGG.TXT
NES Game Genie Code Format DOC v0.71 by Benzene of Digital Emutations
Special thanks to Sardu, Opcode, Deuce, DrSplat, KingPin
NESFQ.HTM
NES Tech FAQ by Chris Covell
NES.HTM
Nintendo Entertainment System Architecture by Marat Fayzullin
Pascal Felber Patrick Lesaard Tink Goroh Pan of Anthrox Bas Vijfwinkel Kawasedo Paul Robson Marcel de Kogel Serge Skorobogatov Alex Krasivsky John Stiles |
KEYBOARD.TXT
Reverse Engineering the Keyboard of Family Computer
by goroh, english translation by Ki
LIGHTGUN.TXT
Family Computer Gun
by goroh, english translation by Ki
POWERPAD.TXT
Power Pad information Version: 1.2 (03/12/00) by Tennessee Carmel-Veilleux
Thanks to Jeremy D. Chadwick, Kevin Horton
CPU
Project64, Graham
女孩不哭(QQ:191035066)@2012-07-18 22:47:13 @ http://www.cnblogs.com/nbsofer
