pcf8951对三个通道的模拟输入进行ad转换，然后把三个转换得到的数字量通过串口通信依次在电脑上显示，Verilog

以下是一个简单的Verilog代码示例，用于将PCF8951的三个通道的模拟输入进行AD转换，并将转换后的数字量通过串口通信依次在电脑上显示。

module pcf8951_ad_to_uart (
  input clk,
  input rst,
  input sda,
  output scl,
  output reg [23:0] uart_data
);

  // 定义PCF8951的I2C设备地址
  parameter PCF8951_ADDRESS = 8'h90;

  // 定义PCF8951的控制字节
  parameter CTRL_BYTE = 8'h04;

  // 定义PCF8951的AD通道
  parameter AD_CHANNEL_0 = 2'h0;
  parameter AD_CHANNEL_1 = 2'h1;
  parameter AD_CHANNEL_2 = 2'h2;

  // 定义状态机的状态
  parameter STATE_IDLE = 2'h0;
  parameter STATE_START = 2'h1;
  parameter STATE_CTRL_BYTE = 2'h2;
  parameter STATE_CONFIG_BYTE = 2'h3;
  parameter STATE_READ_BYTE = 2'h4;

  // 定义状态机的变量
  reg [1:0] state;
  reg [7:0] i2c_address;
  reg [7:0] i2c_data;
  reg [1:0] ad_channel;
  reg [11:0] ad_value;

  // 定义计数器，用于时序控制
  reg [3:0] counter;

  // 初始化状态机和计数器
  initial begin
    state <= STATE_IDLE;
    counter <= 4'b0;
  end

  // 状态机逻辑
  always @(posedge clk) begin
    case (state)
      STATE_IDLE: begin
        if (rst) begin
          state <= STATE_IDLE;
        end else begin
          state <= STATE_START;
        end
      end
      STATE_START: begin
        scl <= 1'b1;
        sda <= 1'b1;
        counter <= counter + 1;
        if (counter == 4'b1) begin
          state <= STATE_CTRL_BYTE;
          i2c_address <= PCF8951_ADDRESS;
        end
      end
      STATE_CTRL_BYTE: begin
        scl <= 1'b0;
        sda <= 1'b0;
        counter <= counter + 1;
        if (counter == 4'b2) begin
          sda <= 1'b1;
          counter <= 4'b0;
          state <= STATE_CONFIG_BYTE;
          i2c_data <= CTRL_BYTE;
        end
      end
      STATE_CONFIG_BYTE: begin
        scl <= 1'b0;
        sda <= 1'b0;
        counter <= counter + 1;
        if (counter == 4'b2) begin
          sda <= 1'b1;
          counter <= 4'b0;
          case (ad_channel)
            AD_CHANNEL_0: begin
              state <= STATE_READ_BYTE;
              i2c_address <= PCF8951_ADDRESS;
            end
            AD_CHANNEL_1: begin
              state <= STATE_CTRL_BYTE;
              i2c_address <= PCF8951_ADDRESS | 1'b1;
            end
            AD_CHANNEL_2: begin
              state <= STATE_CTRL_BYTE;
              i2c_address <= PCF8951_ADDRESS | 1'b0;
            end
          endcase
        end
      end
      STATE_READ_BYTE: begin
        scl <= 1'b1;
        sda <= 1'b1;
        counter <= counter + 1;
        if (counter == 4'b1) begin
          scl <= 1'b0;
          counter <= 4'b0;
          state <= STATE_IDLE;
          ad_value <= {i2c_data, sda};
          uart_data <= {ad_channel, ad_value};
          case (ad_channel)
            AD_CHANNEL_0: begin
              ad_channel <= AD_CHANNEL_1;
            end
            AD_CHANNEL_1: begin
              ad_channel <= AD_CHANNEL_2;
            end
            AD_CHANNEL_2: begin
              ad_channel <= AD_CHANNEL_0;
            end
          endcase
        end
      end
    endcase
  end

endmodule

这个代码使用状态机模拟了PCF8951的I2C通信过程，以便对三个通道的模拟输入进行AD转换。在每个通道的转换完成后，将数字量通过串口通信发送给计算机，并在电脑上显示。请注意，此代码仅为示例，可能需要根据实际需求进行修改和调整。