用verilog实现iic
时间: 2023-12-04 19:10:24 浏览: 37
下面是一个用Verilog HDL实现IIC总线的简单例子:
```verilog
module i2c_controller(
input clk,
input rst,
input sda,
output reg sda_out,
input scl,
output reg scl_out
);
// 状态枚举类型
typedef enum logic [2:0] {
IDLE,
START,
ADDR,
DATA,
ACK,
STOP,
ERROR
} state_e;
reg [7:0] addr; // 设备地址
reg [7:0] data; // 数据
reg [2:0] state; // 状态
reg bit ack; // 应答标志
always @(posedge clk, posedge rst) begin
if (rst) begin
state <= IDLE;
scl_out <= 1'b1;
sda_out <= 1'b1;
addr <= 8'b0;
data <= 8'b0;
ack <= 1'b0;
end
else begin
case (state)
IDLE: begin
if (!sda) begin
state <= START;
end
end
START: begin
sda_out <= 1'b0;
state <= ADDR;
end
ADDR: begin
sda_out <= addr[7];
addr <= {addr[6:0], sda};
if (ack) begin
state <= DATA;
end
end
DATA: begin
sda_out <= data[7];
data <= {data[6:0], sda};
if (ack) begin
state <= STOP;
end
end
ACK: begin
ack <= !sda;
state <= IDLE;
end
STOP: begin
sda_out <= 1'b0;
state <= IDLE;
end
ERROR: begin
// 处理错误情况
end
endcase
end
end
// 时钟延迟函数
function void delay;
input integer n;
begin
integer i;
for (i = 0; i < n; i = i + 1) begin
#1;
end
end
endfunction
// 主设备发送函数
task send;
input integer addr;
input integer data;
begin
state <= START;
delay(10);
addr = addr << 1;
for (int i = 7; i >= 0; i = i - 1) begin
sda_out <= addr[i];
delay(10);
scl_out <= 1'b0;
delay(10);
scl_out <= 1'b1;
delay(10);
end
ack <= 1'b0;
sda_out <= 1'b1;
delay(10);
for (int i = 7; i >= 0; i = i - 1) begin
sda_out <= data[i];
delay(10);
scl_out <= 1'b0;
delay(10);
scl_out <= 1'b1;
delay(10);
end
ack <= 1'b0;
state <= STOP;
delay(10);
sda_out <= 1'b0;
delay(10);
scl_out <= 1'b0;
delay(10);
scl_out <= 1'b1;
delay(10);
sda_out <= 1'b1;
delay(10);
end
endtask
// 从设备接收函数
task receive;
input integer addr;
output reg [7:0] data;
begin
state <= START;
delay(10);
addr = (addr << 1) | 1'b1;
for (int i = 7; i >= 0; i = i - 1) begin
sda_out <= addr[i];
delay(10);
scl_out <= 1'b0;
delay(10);
scl_out <= 1'b1;
delay(10);
end
ack <= 1'b0;
sda_out <= 1'b1;
delay(10);
state <= DATA;
for (int i = 7; i >= 0; i = i - 1) begin
scl_out <= 1'b0;
delay(10);
data[i] <= sda;
scl_out <= 1'b1;
delay(10);
end
ack <= 1'b0;
state <= STOP;
delay(10);
sda_out <= 1'b0;
delay(10);
scl_out <= 1'b0;
delay(10);
scl_out <= 1'b1;
delay(10);
sda_out <= 1'b1;
delay(10);
end
endtask
endmodule
```
这个IIC控制器实现了一个简单的主从模式,包括主设备发送和从设备接收两个基本功能。在发送或接收数据时,控制器会根据时序产生相应的IIC波形,实现数据的传输和接收。除了基本的状态机逻辑,还包括时钟延迟函数和发送/接收任务等。这个例子是一个简单的IIC控制器实现,可以根据具体应用需求进行修改和扩展。