PIC32MZ tutorial -- External Interrupt

　　In my older blog "PIC32MZ tutorial -- Key Debounce", I shows how to acheive key debounce with port polling. At this moment, I write an application which uses External Interrupt.  Therefore, only generates interrupt and starts debounce when the falling or raising edge happens, so it will eliminate the MCU load of port polling. Finally, this application runs wonderfully on PIC32MZ EC Starter Kit. The button on RB14 released, the LED on RH0 lights up. and the button of RB14 pressed, the LED on RH0 puts out. The below is the copy of code of this application.

#include <xc.h>
#include <sys/attribs.h>
#pragma config FMIIEN = ON // Ethernet RMII/MII Enable (MII Enabled) // need a 25MHz XTAL in MII mode, a 50MHz Clock in RMII mode.
#pragma config FETHIO = ON // Ethernet I/O Pin Select (Default Ethernet I/O)
#pragma config PGL1WAY = ON // Permission Group Lock One Way Configuration (Allow only one reconfiguration)
#pragma config PMDL1WAY = ON // Peripheral Module Disable Configuration (Allow only one reconfiguration)
#pragma config IOL1WAY = ON // Peripheral Pin Select Configuration (Allow only one reconfiguration)
#pragma config FUSBIDIO = OFF // USB USBID Selection (Controlled by Port Function)

// DEVCFG2　　7FF9B11A
#pragma config FPLLIDIV = DIV_3 // System PLL Input Divider (3x Divider)
#pragma config FPLLRNG = RANGE_5_10_MHZ // System PLL Input Range (5-10 MHz Input)
#pragma config FPLLICLK = PLL_POSC // System PLL Input Clock Selection (POSC is input to the System PLL)
#pragma config FPLLMULT = MUL_50 // System PLL Multiplier (PLL Multiply by 50)  //PLL must output between 350 and 700 MHz
#pragma config FPLLODIV = DIV_2 // System PLL Output Clock Divider (2x Divider)
#pragma config UPLLFSEL = FREQ_24MHZ // USB PLL Input Frequency Selection (USB PLL input is 24 MHz)
#pragma config UPLLEN = OFF // USB PLL Enable (USB PLL is disabled)

// DEVCFG1　　7F653839
#pragma config FNOSC = SPLL // Oscillator Selection Bits (System PLL)
#pragma config DMTINTV = WIN_127_128 // DMT Count Window Interval (Window/Interval value is 127/128 counter value)
#pragma config FSOSCEN = OFF // Secondary Oscillator Enable (Disable SOSC)
#pragma config IESO = OFF // Internal/External Switch Over (Disabled)
#pragma config POSCMOD = EC // Primary Oscillator Configuration (External clock mode)
#pragma config OSCIOFNC = ON // CLKO Output Signal Active on the OSCO Pin (Enabled)
#pragma config FCKSM = CSDCMD // Clock Switching and Monitor Selection (Clock Switch Disabled, FSCM Disabled)
#pragma config WDTPS = PS32 // Watchdog Timer Postscaler (1:32)
#pragma config WDTSPGM = STOP // Watchdog Timer Stop During Flash Programming (WDT stops during Flash programming)
#pragma config WINDIS = NORMAL // Watchdog Timer Window Mode (Watchdog Timer is in non-Window mode)
#pragma config FWDTEN = OFF // Watchdog Timer Enable (WDT Disabled)
#pragma config FWDTWINSZ = WINSZ_25 // Watchdog Timer Window Size (Window size is 25%)
#pragma config DMTCNT = DMT31 // Deadman Timer Count Selection (2^31 (2147483648))
#pragma config FDMTEN = OFF // Deadman Timer Enable (Deadman Timer is disabled)

// DEVCFG0　　FFFFFFF7
#pragma config DEBUG = OFF // Background Debugger Enable (Debugger is disabled)
#pragma config JTAGEN = ON // JTAG Enable (JTAG Port Enabled)
#pragma config ICESEL = ICS_PGx2 // ICE/ICD Comm Channel Select (Communicate on PGEC2/PGED2)
#pragma config TRCEN = ON // Trace Enable (Trace features in the CPU are enabled)
#pragma config BOOTISA = MIPS32 // Boot ISA Selection (Boot code and Exception code is MIPS32)
#pragma config FECCCON = OFF_UNLOCKED // Dynamic Flash ECC Configuration (ECC and Dynamic ECC are disabled (ECCCON bits are writable))
#pragma config FSLEEP = OFF // Flash Sleep Mode (Flash is powered down when the device is in Sleep mode)
#pragma config DBGPER = ALLOW_PG2 // Debug Mode CPU Access Permission (Allow CPU access to Permission Group 2 permission regions)
#pragma config EJTAGBEN = NORMAL // EJTAG Boot (Normal EJTAG functionality)

// DEVCP0
#pragma config CP = OFF // Code Protect (Protection Disabled)

#define Sys_Conf()          PRECON = 0x12  

#define LED_IOCTL()       TRISHCLR = (1<<0)
#define LED_SETON()       LATHSET = (1<<0)
#define LED_SETOFF()      LATHCLR = (1<<0)
#define LED_ONOFF()       LATHINV = (1<<0)
#define LED_OPEN()        ANSELH &= 0xFFFFFFFE

typedef enum _LED_STATE_t {
        /* Describe structure member. */
        OFF = 0,

        /* Describe structure member. */
        ON = 1

    } LED_STATE_t;
    
LED_STATE_t PreLedState, LedState;

#define DEBOUNCE_Input          (PORTB & 0x4000)
#define DEBOUNCE_Open()         ANSELB = 0xFFFFBFFF
#define DEBOUNCE_IOCtl()        CNPUBSET = 0x4000
#define DEBOUNCE_Output         LedState
#define DEBOUNCE_ThreholdLow    0
#define DEBOUNCE_ThreholdHigh   100

volatile unsigned char DEBOUNCE_EventStart;
    //volatile unsigned char DEBOUNCE_TimeFlag;
    unsigned long DEBOUNCE_PreInput;
    unsigned int DEBOUNCE_Integrator;

    void Key_Init(void)
    {
        DEBOUNCE_EventStart = 0;
        DEBOUNCE_Integrator = DEBOUNCE_ThreholdHigh / 2;
        //DEBOUNCE_TimeFlag = 0;
        
        DEBOUNCE_Open();
        DEBOUNCE_IOCtl();
        DEBOUNCE_PreInput = DEBOUNCE_Input;
        
        //Pps_UnLock();
        INT1R = 0x2;
        //Pps_Lock();
        INTCONCLR = 0x2;
        
        IPC2SET = 0x10;
        IFS0CLR = 0x100;
        IEC0SET = 0x100;
        //CNENBSET = 0x1000;
        //IPC29SET = 0x12000000;
        //IFS3CLR = 0x800000;
        //IEC3SET = 0x800000;
        //CNCONBSET = 0x8000;
    }

    //void Key_Scheduler(void)
    void Key_Debounce(void)
    {
        //if (DEBOUNCE_TimeFlag)
        //{
            if (DEBOUNCE_EventStart)
            {
                if (DEBOUNCE_Input == 0)
                {
                    if (DEBOUNCE_Integrator-- == DEBOUNCE_ThreholdLow)
                    {
                        DEBOUNCE_Output = 0;
                        DEBOUNCE_PreInput = DEBOUNCE_Input;
                        DEBOUNCE_EventStart = 0;
                        DEBOUNCE_Integrator = DEBOUNCE_ThreholdHigh / 2;
                    }
                }
                else                   //if (DEBOUNCE_Input == 1)
                {
                    if (DEBOUNCE_Integrator++ == DEBOUNCE_ThreholdHigh)
                    {
                        DEBOUNCE_Output = 1;
                        DEBOUNCE_PreInput = DEBOUNCE_Input;
                        DEBOUNCE_EventStart = 0;
                        DEBOUNCE_Integrator = DEBOUNCE_ThreholdHigh / 2;
                    }
                }
            }
            //else if (DEBOUNCE_PreInput != DEBOUNCE_Input)
            //{
               // DEBOUNCE_EventStart = 1;
            //}
            //DEBOUNCE_TimeFlag = 0;
        //}
    }

void Led_Init(void)
{
    LED_OPEN();
    LED_IOCTL();
    LED_SETON();
    LedState = ON;
    PreLedState = LedState;
}

void Tmr1_Init(void)
{
    T1CON = 0x8010;
    PR1 = 0x30D3;
    IPC1SET = 0x5;
    TMR1 = 0;
    IEC0SET = 0x10;
    IFS0CLR = 0x10;
}

void Tmr1_Write(unsigned int value)
{
    TMR1 = value & 0xFFFF;
}

void __ISR(_EXTERNAL_1_VECTOR,ipl4AUTO) Ext1_Handler(void)
{
    if ((INTCON & 0x2) == 0)
    {
        INTCONSET = 0x2;
    }
    else
    {
        INTCONCLR = 0x2;
    }
    DEBOUNCE_EventStart = 1;
    IFS0CLR = 0x100; // Clear flag
 }

void __ISR(_TIMER_1_VECTOR,ipl1AUTO) Timer1_Handler(void)
{
    //DEBOUNCE_TimeFlag = 1;
    Key_Debounce();
    Tmr1_Write(0);
    IFS0CLR = 0x10; // Clear flag
 }

void main(void) 
{
    Sys_Conf();
    //Wdt_Init();
    Led_Init();
    Key_Init();
    Tmr1_Init();
    Mvec_Interrupt();
    
    while (1)
    {
        //Wdt_Refresh();
        //Key_Scheduler();
        Led_Scheduler();
    }
}