用状态机实现通用多字节SPI接口模块
这次设计一个通用的多字节SPI接口模块，特点如下：
- 可以设置为1-128字节的SPI通信模块
- 可以修改CPOL、CPHA来进行不同的通信模式
- 可以设置输出的时钟
状态转移图和思路与多字节串口发送模块一样，这里就不给出了，具体可看该随笔。
一、模块代码
1、需要的模块
通用8位SPI接口模块
`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:
// Engineer: Lclone
//
// Create Date: 2023/01/23 00:56:52
// Design Name: SPI_Interface
// Module Name: SPI_Interface
// Project Name:
// Target Devices:
// Tool Versions:
// Description:
// SPI接口模块
// 可修改分频参数来生成目标频率，最低分频系数为2；
// 可以置位CPOL、CPHA可以来设置通信模式；
// 本模块只有1位，但是可以简单修改位宽来设置多位片选信号；
// 注意：本模块先传最高字节的数据。
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module SPI_Interface
# (
parameter Value_divide = 2)//分频系数（最低为2）
(
//-----------------内部接口------------------
input Clk, //时钟
input Rst_n, //复位信号
input CPOL, //时钟极性
input CPHA, //时钟相位
input CS_input, //片选信号
input Send_en, //发送使能
input [7:0] Data_send, //待发送数据
output reg Read_en, //接收数据读使能
output reg [7:0] Data_recive, //接收到的数据
//------------------外部接口------------------
output reg Spi_clk, //输出时钟端
output reg Spi_mosi, //主输出从接收端
input Spi_miso, //主接收从输出端
output Cs_output //片选信号输出
);
reg act_flag; //活动状态寄存器
reg [9:0] cnt_divide; //分频计数器
reg [7:0] Data_send_reg; //带发送数据寄存器
reg [4:0] cnt_pulse; //脉冲计数器
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
act_flag <= 0;
else if(Send_en == 1)
act_flag <= 1;
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1 & cnt_pulse == 16)
act_flag <= 0;
else
act_flag <= act_flag;
end
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
Read_en <= 0;
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1 & cnt_pulse == 16)
Read_en <= 1;
else
Read_en <= 0;
end
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
Data_send_reg <= 0;
else if(Send_en == 1)
Data_send_reg <= Data_send;
else
Data_send_reg <= Data_send_reg;
end
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
cnt_divide <= 0;
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1)
cnt_divide <= 0;
else if(act_flag == 1)
cnt_divide <= cnt_divide + 1'b1;
else
cnt_divide <= 0;
end
always @(posedge Clk or negedge Rst_n) begin//生成目标时钟两倍频率的的cnt_pulse
if(Rst_n == 0)
cnt_pulse <= 0;
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1 & cnt_pulse == 16)
cnt_pulse <= 0;
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1)
cnt_pulse <= cnt_pulse + 1'b1;
else if(act_flag == 1)
cnt_pulse <= cnt_pulse;
else
cnt_pulse <= 0;
end
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
begin
if(CPOL == 1)
begin
Spi_clk <= 1;
Spi_mosi <= 1;
Data_recive <= 0;
end
else
begin
Spi_clk <= 0;
Spi_mosi <= 1;
Data_recive <= 0;
end
end
else if(cnt_divide == Value_divide/2 - 1 & act_flag == 1)
begin
if(CPHA == 0)
case(cnt_pulse)
0:begin
Spi_clk <= Spi_clk;
Spi_mosi <= Data_send_reg[7];
Data_recive <= Data_recive;
end
1:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[7] <= Spi_miso;
end
2:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[6];
Data_recive <= Data_recive;
end
3:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[6] <= Spi_miso;
end
4:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[5];
Data_recive <= Data_recive;
end
5:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[5] <= Spi_miso;
end
6:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[4];
Data_recive <= Data_recive;
end
7:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[4] <= Spi_miso;
end
8:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[3];
Data_recive <= Data_recive;
end
9:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[3] <= Spi_miso;
end
10:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[2];
Data_recive <= Data_recive;
end
11:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[2] <= Spi_miso;
end
12:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[1];
Data_recive <= Data_recive;
end
13:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[1] <= Spi_miso;
end
14:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[0];
Data_recive <= Data_recive;
end
15:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[0] <= Spi_miso;
end
16:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= 1;
Data_recive <= Data_recive;
end
default:;
endcase
else
case(cnt_pulse)
0:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[7];
Data_recive <= Data_recive;
end
1:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[7] <= Spi_miso;
end
2:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[6];
Data_recive <= Data_recive;
end
3:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[6] <= Spi_miso;
end
4:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[5];
Data_recive <= Data_recive;
end
5:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[5] <= Spi_miso;
end
6:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[4];
Data_recive <= Data_recive;
end
7:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[4] <= Spi_miso;
end
8:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[3];
Data_recive <= Data_recive;
end
9:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[3] <= Spi_miso;
end
10:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[2];
Data_recive <= Data_recive;
end
11:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[2] <= Spi_miso;
end
12:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[1];
Data_recive <= Data_recive;
end
13:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[1] <= Spi_miso;
end
14:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Data_send_reg[0];
Data_recive <= Data_recive;
end
15:begin
Spi_clk <= ~Spi_clk;
Spi_mosi <= Spi_mosi;
Data_recive[0] <= Spi_miso;
end
16:begin
Spi_clk <= Spi_clk;
Spi_mosi <= 1;
Data_recive <= Data_recive;
end
default:;
endcase
end
end
assign Cs_output = CS_input;
endmodule
2、设计的模块
`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: GDUT
// Engineer: Lclone
//
// Create Date: 2023/01/23 22:12:11
// Design Name: SPI_Bytes
// Module Name: SPI_Bytes
// Project Name:
// Target Devices:
// Tool Versions:
// Description:
// - 可以设置为1-128字节的SPI通信模块
// - 可以修改CPOL、CPHA来进行不同的通信模式
// - 可以设置输出的时钟
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module SPI_Bytes
# (
parameter Data_Width = 16, //数据位宽
parameter ROUNDS = Data_Width/8) //传输轮数（例化时不需要设置）
(
//-----------------内部接口--------------------
input Clk, //时钟信号
input Rst_n, //复位信号
input [Data_Width-1:0] Send_Bytes_Data, //发送的多字节数据
input Bytes_Send_en, //多字节发送使能
output reg [Data_Width-1:0] Recive_Bytes_Data, //接收的多字节数据
output reg Bytes_Read_en, //多字节读使能
input Cs_input, //片选信号输入
//-----------------外部接口--------------------
output Spi_mosi, //主输出从输入
input Spi_miso, //主输入从输出
output Spi_clk, //输出时钟
output Cs_output //片选信号输出
);
reg send_en; //发送使能
wire read_en; //读使能
reg [7:0] data_send; //待发送数据
reg [Data_Width-1:0] Send_Bytes_Data_reg; //多字节数据寄存器
wire[7:0] data_recive; //接收的数据
reg [9:0] round; //发送次数（修改该位宽可改变最大发送数据位宽）
reg [1:0] state; //状态寄存器
always @(posedge Clk or negedge Rst_n) begin
if(Rst_n == 0)
round <= 0;
else if(round == ROUNDS)
round <= 0;
else if(read_en == 1)
round <= round + 1'b1;
else
round <= round;
end
always @(posedge Clk or negedge Rst_n) begin//状态机
if(Rst_n == 0)
begin
state <= 0;
Bytes_Read_en <= 0;
data_send <= 0;
Send_Bytes_Data_reg <= 0;
send_en <= 0;
Recive_Bytes_Data <= 0;
end
else case(state)
0://空闲状态
begin
Bytes_Read_en <= 0;
if(Bytes_Send_en == 1)
begin
state <= 1;
Send_Bytes_Data_reg <= Send_Bytes_Data;
end
else
state <= 0;
end
1://发送与接收状态
begin
send_en <= 0;
if(round == ROUNDS)
begin
state <= 0;
Bytes_Read_en <= 1;
Recive_Bytes_Data[7:0] <= data_recive;//由于发送和接收的时序略有不同，这里给接收做个补偿。
end
else
begin
state <= 2;
send_en <= 1;
data_send <= Send_Bytes_Data_reg[Data_Width-1:Data_Width-8];//发送高位
Recive_Bytes_Data[7:0] <= data_recive;//把接收到的数据放在低位
end
end
2://数据移位
begin
send_en <= 0;
if(read_en == 1)
begin
Send_Bytes_Data_reg <= Send_Bytes_Data_reg << 8;//高位刷新
Recive_Bytes_Data <= Recive_Bytes_Data << 8;//把低位的数据移到高位
state <= 1;
end
else
state <= 2;
end
default:;
endcase
end
SPI_Interface
# (
.Value_divide (4)) //分频系数
SPI_SPI_Interface_inst
(
//-----------------内部接口------------------
.Clk (Clk), //时钟信号
.Rst_n (Rst_n), //复位信号
.CPOL (1),
.CPHA (0),
.CS_input (1), //片选输入
.Send_en (send_en), //发送使能
.Data_send (data_send), //待发送数据
.Read_en (read_en), //读使能
.Data_recive (data_recive), //接收的数据
//------------------外部接口------------------
.Spi_clk (Spi_clk), //输出时钟
.Spi_mosi (Spi_mosi), //主输出从输入
.Spi_miso (Spi_miso), //主输入从输出
.Cs_output (Cs_output) //片选输出
);
endmodule
二、仿真
1、仿真激励
`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:
// Engineer:
//
// Create Date: 2023/01/26 16:00:48
// Design Name:
// Module Name: SPI_Bytes_tb
// Project Name:
// Target Devices:
// Tool Versions:
// Description:
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module SPI_Bytes_tb();
reg clk_50m;
initial clk_50m <= 1;
always #10 clk_50m <= ~clk_50m;
reg rst_n;
initial begin
rst_n <= 0;
#200
rst_n <= 1;
end
reg Bytes_Send_en;
reg [31:0] Send_Bytes_Data;
wire Bytes_Read_en;
wire [31:0] Recive_Bytes_Data;
wire Spi_clk;
wire Spi_mosi;
wire Spi_miso;
wire Cs_output;
SPI_Bytes
# (
.Data_Width (32))//数据位宽为32位
SPI_Bytes_inst
(
//-----------------内部接口--------------------
.Clk (clk_50m),
.Rst_n (rst_n),
.Send_Bytes_Data (Send_Bytes_Data),
.Bytes_Send_en (Bytes_Send_en),
.Recive_Bytes_Data (Recive_Bytes_Data),
.Bytes_Read_en (Bytes_Read_en),
.Cs_input (1'b1),
//-----------------外部接口--------------------
.Spi_mosi (Spi_mosi),
.Spi_miso (Spi_miso),
.Spi_clk (Spi_clk),
.Cs_output (Cs_output)
);
assign Spi_miso = Spi_mosi;
initial begin
Bytes_Send_en <= 0;
Send_Bytes_Data <= 0;
#400;
Bytes_Send_en <= 1;
Send_Bytes_Data <= 32'h89abcdef;
#20
Bytes_Send_en <= 0;
#4000;
Bytes_Send_en <= 1;
Send_Bytes_Data <= 32'h12345678;
#20
Bytes_Send_en <= 0;
end
endmodule
2、仿真结果
仿真结果：两次多字节发送都能正确的发送和接收数据，且能正确的生成Bytes_Read_en信号。模块仿真验证可行。
