iic总线verilog代码

以下是一段简单的I2C总线的Verilog代码，其中包括了I2C总线传输过程中的起始信号、地址信号、数据信号和停止信号的控制。

module i2c_master(
  input clk,
  input rst,
  input sda_i,
  output sda_o,
  inout scl
);

  parameter IDLE = 2'b00;
  parameter START = 2'b01;
  parameter STOP = 2'b10;
  parameter DATA = 2'b11;

  reg [7:0] data_reg;
  reg [6:0] addr_reg;
  reg [1:0] state;
  reg [1:0] bit_cnt;
  reg scl_dir;
  reg sda_dir;
  reg sda;
  reg data_out;
  wire sda_i_int;

  assign sda_i_int = (sda_dir) ? sda_i : 1'bZ;
  assign sda_o = (sda_dir) ? data_out : 1'bZ;

  always @ (posedge clk or posedge rst) begin
    if (rst) begin
      state <= IDLE;
      bit_cnt <= 0;
      scl_dir <= 1'b0;
      sda_dir <= 1'b0;
      sda <= 1'b1;
      data_out <= 1'b1;
      addr_reg <= 0;
      data_reg <= 0;
    end else begin
      case (state)
        IDLE: begin
          if (sda_i_int == 1'b0) begin
            state <= START;
          end
        end

        START: begin
          sda_dir <= 1'b1;
          sda <= 1'b0;
          scl_dir <= 1'b1;
          data_out <= 1'b1;
          bit_cnt <= 7;
          state <= ADDR;
        end

        ADDR: begin
          sda_dir <= 1'b0;
          sda <= addr_reg[bit_cnt];
          scl_dir <= 1'b1;
          if (bit_cnt == 0) begin
            if (sda_i_int == 1'b1) begin
              state <= DATA;
              bit_cnt <= 7;
            end else begin
              state <= STOP;
            end
          end else begin
            bit_cnt <= bit_cnt - 1;
          end
        end

        DATA: begin
          sda_dir <= 1'b0;
          sda <= data_reg[bit_cnt];
          scl_dir <= 1'b1;
          if (bit_cnt == 0) begin
            state <= STOP;
          end else begin
            bit_cnt <= bit_cnt - 1;
          end
        end

        STOP: begin
          sda_dir <= 1'b1;
          sda <= 1'b0;
          scl_dir <= 1'b0;
          data_out <= 1'b1;
          bit_cnt <= 0;
          state <= IDLE;
        end
      endcase
    end
  end

  always @ (posedge scl or negedge scl) begin
    if (rst) begin
      sda_dir <= 1'b0;
      sda <= 1'b1;
      scl_dir <= 1'b0;
    end else begin
      if (scl_dir == 1'b1 && scl == 1'b0) begin
        scl_dir <= 1'b0;
        if (state == IDLE) begin
          sda_dir <= 1'b1;
        end else begin
          sda_dir <= 1'b0;
          data_out <= (state == DATA) ? data_reg[bit_cnt] : 1'b1;
        end
      end else if (scl_dir == 1'b0 && scl == 1'b1) begin
        scl_dir <= 1'b1;
        if (state == IDLE || state == STOP) begin
          sda_dir <= 1'b0;
        end else begin
          sda_dir <= 1'b1;
          if (state == ADDR) begin
            addr_reg <= {addr_reg[6:0], sda_i_int};
          end else if (state == DATA) begin
            data_reg <= {data_reg[6:0], sda_i_int};
          end
          bit_cnt <= bit_cnt - 1;
        end
      end
    end
  end

endmodule

请注意，这只是一个简化的例子，实际的I2C总线控制器需要更多的功能和错误检查。此外，还需要与其他I2C设备的物理层接口进行匹配。