使用verilog语言写一个IIC协议

以下是一个简单的I2C Master的Verilog实现：

module i2c_master(
    input clk,
    input reset,
    input start,
    input stop,
    input [7:0] slave_address,
    input [7:0] data_in,
    output reg data_out,
    output reg ack,
    output reg busy
);

// I2C状态机的状态定义
parameter IDLE = 2'b00;
parameter START = 2'b01;
parameter ADDRESS = 2'b10;
parameter DATA = 2'b11;

// I2C状态机的寄存器
reg [1:0] state_reg;
reg [7:0] data_reg;
reg [7:0] address_reg;
reg [7:0] bit_counter_reg;

// I2C时序的计数器
reg [7:0] counter_reg;

// 初始化I2C状态机和时序计数器
initial begin
    state_reg <= IDLE;
    counter_reg <= 8'd0;
    bit_counter_reg <= 8'd0;
end

// I2C状态机的组合逻辑
always @(*) begin
    case(state_reg)
        IDLE: begin
            data_out <= 1'b1;
            ack <= 1'b1;
            busy <= 1'b0;
            if(start) begin
                state_reg <= START;
            end
        end
        START: begin
            data_out <= 1'b0;
            ack <= 1'b0;
            busy <= 1'b1;
            if(counter_reg == 8'd7) begin
                state_reg <= ADDRESS;
                address_reg <= slave_address;
                bit_counter_reg <= 8'd0;
            end else begin
                counter_reg <= counter_reg + 1;
            end
        end
        ADDRESS: begin
            data_out <= address_reg[7];
            ack <= 1'b0;
            busy <= 1'b1;
            if(counter_reg == 8'd15) begin
                state_reg <= DATA;
                bit_counter_reg <= 8'd0;
                if(data_in) begin
                    data_reg <= data_in;
                end
            end else begin
                address_reg <= {address_reg[6:0], 1'b0};
                counter_reg <= counter_reg + 1;
            end
        end
        DATA: begin
            data_out <= data_reg[7];
            ack <= 1'b0;
            busy <= 1'b1;
            if(counter_reg == 8'd23) begin
                state_reg <= IDLE;
                if(stop) begin
                    data_out <= 1'b0;
                    ack <= 1'b0;
                end
            end else begin
                data_reg <= {data_reg[6:0], 1'b0};
                counter_reg <= counter_reg + 1;
            end
        end
    endcase
end

// I2C时序的时钟处理
always @(posedge clk or posedge reset) begin
    if(reset) begin
        counter_reg <= 8'd0;
    end else begin
        if(state_reg == START || state_reg == ADDRESS || state_reg == DATA) begin
            counter_reg <= counter_reg + 1;
            if(counter_reg == 8'd23) begin
                counter_reg <= 8'd0;
                ack <= 1'b1;
                if(state_reg == DATA) begin
                    if(bit_counter_reg == 8'd7) begin
                        bit_counter_reg <= 8'd0;
                        data_reg <= data_in;
                    end else begin
                        data_reg <= {data_reg[6:0], 1'b0};
                        bit_counter_reg <= bit_counter_reg + 1;
                    end
                end
            end
        end
    end
end

endmodule

这个模块接收时钟、复位、启动位、停止位、从设备地址和数据输入，并在数据输出、应答和忙标志中提供I2C Master的功能。你可以使用它来与I2C从设备通信。