使用Verilog写一段IIC读写EEPROM的代码

以下是一段简单的Verilog代码，用于在IIC总线上读取和写入EEPROM：

module iic_eeprom(
  input clk,
  input rst,
  input sda,
  input scl,
  input [7:0] slave_addr,
  input [7:0] mem_addr,
  inout [7:0] data,
  input wr_en,
  input rd_en,
  output done
);

parameter IDLE = 2'b00, START = 2'b01, ADDR = 2'b10, DATA = 2'b11;
reg [1:0] state = IDLE;
reg [7:0] tx_data;
reg [7:0] rx_data;
reg [7:0] counter = 8'h00;
reg [7:0] bit_counter = 8'h00;
reg [7:0] addr_counter = 8'h00;
reg [7:0] ack;
reg [7:0] stop;
wire [7:0] bus;
assign bus = (state == DATA) ? tx_data : 8'b11111110;

i2c_slave i2c_slave_0 (
  .clk(clk),
  .rst(rst),
  .sda(sda),
  .scl(scl),
  .bus(bus),
  .ack(ack),
  .stop(stop)
);

always @(posedge clk) begin
  if (rst) begin
    state <= IDLE;
    counter <= 8'h00;
    bit_counter <= 8'h00;
    addr_counter <= 8'h00;
    done <= 1'b0;
  end else begin
    case (state)
      IDLE: begin
        if (rd_en || wr_en) begin
          state <= START;
          counter <= 8'h00;
          bit_counter <= 8'h00;
          addr_counter <= 8'h00;
        end else begin
          done <= 1'b1;
        end
      end
      START: begin
        if (stop) begin
          state <= IDLE;
        end else begin
          if (counter == 8'h00) begin
            tx_data <= slave_addr << 1;
            bit_counter <= 8'h00;
            ack <= 1'b0;
            counter <= 8'h01;
          end else if (bit_counter == 8'h07) begin
            state <= ADDR;
            counter <= 8'h01;
            addr_counter <= 8'h00;
          end else begin
            tx_data <= {tx_data[6:0], sda};
            bit_counter <= bit_counter + 8'h01;
            counter <= counter + 8'h01;
          end
        end
      end
      ADDR: begin
        if (stop) begin
          state <= IDLE;
        end else begin
          if (counter == 8'h00) begin
            tx_data <= mem_addr;
            bit_counter <= 8'h00;
            ack <= 1'b0;
            counter <= 8'h01;
          end else if (bit_counter == 8'h07) begin
            if (wr_en) begin
              state <= DATA;
              counter <= 8'h01;
            end else begin
              state <= START;
              counter <= 8'h01;
              bit_counter <= 8'h00;
            end
          end else begin
            tx_data <= {tx_data[6:0], sda};
            bit_counter <= bit_counter + 8'h01;
            counter <= counter + 8'h01;
          end
        end
      end
      DATA: begin
        if (stop) begin
          state <= IDLE;
        end else begin
          if (counter == 8'h00) begin
            if (wr_en) begin
              tx_data <= data;
              bit_counter <= 8'h00;
              ack <= 1'b0;
              counter <= 8'h01;
            end else begin
              state <= START;
              counter <= 8'h01;
              bit_counter <= 8'h00;
            end
          end else if (bit_counter == 8'h07) begin
            if (wr_en) begin
              state <= START;
              counter <= 8'h01;
              bit_counter <= 8'h00;
            end else begin
              state <= DATA;
              counter <= 8'h01;
            end
          end else begin
            tx_data <= {tx_data[6:0], sda};
            bit_counter <= bit_counter + 8'h01;
            counter <= counter + 8'h01;
          end
        end
      end
    endcase
  end
end

always @(posedge clk) begin
  if (ack && state == START) begin
    state <= ADDR;
    counter <= 8'h01;
    bit_counter <= 8'h00;
  end else if (ack && state == ADDR) begin
    if (wr_en) begin
      state <= DATA;
      counter <= 8'h01;
    end else begin
      state <= START;
      counter <= 8'h01;
      bit_counter <= 8'h00;
    end
  end else if (ack && state == DATA) begin
    if (wr_en) begin
      state <= START;
      counter <= 8'h01;
      bit_counter <= 8'h00;
    end else begin
      rx_data <= bus;
      state <= DATA;
      counter <= counter + 8'h01;
      bit_counter <= bit_counter + 8'h01;
      if (bit_counter == 8'h07) begin
        if (counter == 8'h01) begin
          ack <= 1'b0;
        end else begin
          ack <= 1'b1;
        end
      end
    end
  end else if (stop) begin
    state <= IDLE;
  end else begin
    ack <= 1'b1;
  end
end

assign data = rx_data;

endmodule

该代码使用了一个名为`i2c_slave`的模块，它实现了IIC总线的从设备功能。在顶层模块中，我们定义了一些输入和输出，包括时钟和复位信号、SDA和SCL线、从设备地址、内存地址、数据、写入和读取使能信号以及完成信号。我们还定义了一些状态变量和计数器，用于控制IIC通信的过程。在每个时钟周期中，我们根据当前状态执行不同的操作，以实现EEPROM的读取和写入。最后，在完成通信后，我们设置完成信号以通知上层模块。