用verilog写一个IIC接口

以下是一个简单的 Verilog 代码，用于实现 I2C 接口：

module i2c (
    input clk,
    input rst,
    input sda_i,
    output sda_o,
    inout scl,
    input [7:0] slave_addr,
    input [7:0] data_in,
    output reg data_out,
    input wr,
    output reg ack
);

// 定义常量
parameter IDLE = 2'b00;
parameter START = 2'b01;
parameter ADDR = 2'b10;
parameter DATA = 2'b11;

// 定义状态机
reg [1:0] state;
reg [7:0] cnt;
reg [7:0] data_reg;
reg [7:0] addr_reg;

// 初始化状态机
initial begin
    state <= IDLE;
end

// 初始值
assign sda_o = 1'b1;

// 状态机
always @(posedge clk) begin
    if (rst) begin
        state <= IDLE;
        cnt <= 8'd0;
        addr_reg <= 8'd0;
        data_reg <= 8'd0;
        ack <= 1'b0;
        data_out <= 1'b0;
    end
    else begin
        case (state)
            IDLE: begin
                if (wr) begin
                    state <= ADDR;
                    cnt <= 8'd0;
                    addr_reg <= slave_addr;
                end
                else begin
                    state <= ADDR;
                    cnt <= 8'd0;
                    addr_reg <= slave_addr | 8'h01;
                end
            end
            START: begin
                sda_o <= 1'b0;
                if (cnt == 8'd7) begin
                    sda_o <= 1'b1;
                    state <= ADDR;
                    cnt <= 8'd0;
                end
                else begin
                    cnt <= cnt + 1;
                end
            end
            ADDR: begin
                sda_o <= addr_reg[7];
                if (cnt == 8'd7) begin
                    if (sda_i == 1'b0) begin
                        ack <= 1'b1;
                        state <= DATA;
                        cnt <= 8'd0;
                    end
                    else begin
                        ack <= 1'b0;
                        state <= IDLE;
                    end
                end
                else begin
                    addr_reg <= addr_reg << 1;
                    cnt <= cnt + 1;
                end
            end
            DATA: begin
                if (wr) begin
                    sda_o <= data_reg[7];
                    if (cnt == 8'd7) begin
                        if (sda_i == 1'b0) begin
                            ack <= 1'b1;
                            state <= DATA;
                            cnt <= 8'd0;
                            data_reg <= data_in;
                        end
                        else begin
                            ack <= 1'b0;
                            state <= IDLE;
                        end
                    end
                    else begin
                        data_reg <= data_reg << 1;
                        cnt <= cnt + 1;
                    end
                end
                else begin
                    sda_o <= 1'b1;
                    if (cnt == 8'd7) begin
                        data_out <= sda_i;
                        state <= DATA;
                        cnt <= 8'd0;
                    end
                    else begin
                        cnt <= cnt + 1;
                    end
                end
            end
            default: state <= IDLE;
        endcase
    end
end

// 时钟周期处理
always @(posedge clk) begin
    if (rst) begin
        scl <= 1'b1;
    end
    else begin
        if (state == IDLE) begin
            scl <= 1'b1;
        end
        else if (state == DATA && wr) begin
            if (cnt == 8'd7) begin
                scl <= 1'b0;
            end
            else begin
                scl <= 1'b1;
            end
        end
        else begin
            scl <= 1'b0;
        end
    end
end

endmodule

这是一个简单的 I2C 接口实现，适用于基本的通信。您可以根据需要进行修改和优化。