写一个I2C读写eeprom的verilog的程序

在Verilog语言中编写一个I2C（Inter-Integrated Circuit）协议用于读写EEPROM（Electrically Erasable Programmable Read-Only Memory）的模块通常是这样的。以下是一个简化的示例，假设我们正在使用的是SMBus兼容的接口：

module i2c_eeprom_read_write(
    input wire clk,       // I2C clock signal
    input wire sda,       // SDA (Serial Data) line
    input wire scl,       // SCL (Serial Clock) line
    input wire write_en,  // Write enable signal (0 for read, 1 for write)
    input [7:0] addr,   // I2C address of the EEPROM
    input [7:0] data_in, // Data to be written or read
    output reg [7:0] data_out // Data read from EEPROM
);

// SMBus signals and delays for I2C protocol
reg [1:0] read_write;
reg [2:0] nack;
integer delay = 4;

always @(posedge clk or negedge scl) begin
    case(scl)
        1'b0: begin
            if(!sda && !write_en) begin
                read_write <= 2'b00; // Start condition
                nack <= 3'b000;
            end else if(read_write == 2'b00 && !nack[2]) begin
                // Address phase
                sda <= addr ? 1'b0 : 1'b1; // Address byte transmission
                read_write <= 2'b01;
            end else if(read_write == 2'b01 && !nack[1]) begin
                // Command phase
                sda <= write_en ? 1'b1 : 1'b0; // Write command (0x06) or read command (0x05)
                nack <= 3'b000;
            end else if(read_write == 2'b01 && !nack[0]) begin
                // Data phase
                sda <= data_in[0]; // Send first data byte
                read_write <= 2'b10;
                delay_loop:
                    repeat(delay);
            end else if(read_write == 2'b10 && !nack[0]) begin
                // Repeat byte if needed
                if(data_in[1] != 0) begin
                    sda <= data_in[1];
                    goto delay_loop;
                end else begin
                    read_write <= 2'b11;
                    nack <= 3'b000;
                end
            end else if(read_write == 2'b11 && !nack[0]) begin
                // Stop condition
                sda <= 1'b1;
                read_write <= 2'b00;
            end
        end
        1'b1: begin
            // NACK handling
            if(nack[0] && !sda) begin
                read_write <= 2'b00; // Restart condition
                nack <= 3'b000;
            end else begin
                nack <= {nack[1:0], ~sda}; // Shift nack register
            end
        end
    endcase
end

// Data transfer in separate process for readability
process(clk)
begin
    if(rising_edge(clk)) begin
        if(read_write == 2'b10 || read_write == 2'b11) begin
            data_out <= sda;
        end
    end
end

endmodule