iic从机verilog
时间: 2023-07-05 07:14:51 浏览: 53
以下是一个简单的 I2C 从机的 Verilog 代码示例:
```verilog
module i2c_slave(
input clk, // 时钟信号
input reset, // 复位信号
input sda, // SDA 数据线
input scl, // SCL 时钟线
output reg ack, // 应答信号
output reg [7:0] data, // 数据线
output reg done // 完成信号
);
// 定义状态机枚举类型
typedef enum logic [2:0] {
IDLE,
RECEIVE_ADDR,
RECEIVE_DATA,
TRANSMIT_DATA
} state_t;
// 定义状态机变量和寄存器
state_t state, next_state;
reg [7:0] addr_reg, data_reg;
reg [2:0] bit_cnt;
// 默认状态为 IDLE
always @ (posedge clk, posedge reset) begin
if (reset) begin
state <= IDLE;
ack <= 1'b0;
bit_cnt <= 3'b0;
data <= 8'h00;
done <= 1'b0;
end
else begin
state <= next_state;
ack <= 1'b0;
end
end
// 状态机逻辑
always @* begin
case (state)
IDLE: begin
if (~sda & scl) begin
next_state = RECEIVE_ADDR;
bit_cnt = 3'b0;
end
else if (sda & ~scl) begin
next_state = TRANSMIT_DATA;
bit_cnt = 3'b0;
end
else begin
next_state = IDLE;
bit_cnt = 3'b0;
end
end
RECEIVE_ADDR: begin
if (scl) begin
addr_reg[bit_cnt] <= sda;
bit_cnt <= bit_cnt + 1;
if (bit_cnt == 3'b111) begin
next_state = RECEIVE_DATA;
bit_cnt = 3'b0;
end
end
else begin
next_state = RECEIVE_ADDR;
bit_cnt = 3'b0;
end
end
RECEIVE_DATA: begin
if (scl) begin
data_reg[bit_cnt] <= sda;
bit_cnt <= bit_cnt + 1;
if (bit_cnt == 3'b111) begin
next_state = IDLE;
bit_cnt = 3'b0;
data <= data_reg;
done <= 1'b1;
ack <= 1'b1;
end
end
else begin
next_state = RECEIVE_DATA;
bit_cnt = 3'b0;
end
end
TRANSMIT_DATA: begin
if (scl) begin
data_reg <= data;
sda <= data_reg[bit_cnt];
bit_cnt <= bit_cnt + 1;
if (bit_cnt == 3'b111) begin
next_state = IDLE;
bit_cnt = 3'b0;
end
end
else begin
next_state = TRANSMIT_DATA;
bit_cnt = 3'b0;
end
end
default: begin
next_state = IDLE;
bit_cnt = 3'b0;
end
endcase
end
endmodule
```
这个代码实现了一个简单的 I2C 从机,可以接收来自主机的读/写命令,并给出相应的应答信号和数据。需根据具体的 I2C 总线时序和从机地址等参数进行修改和优化。