fpga Verilog四人抢答器

根据提供的引用内容，以下是一个使用Verilog HDL语言设计的四人抢答器的示例：

module FourPlayerQuizzer(
  input wire clk,
  input wire reset,
  input wire start,
  output wire [3:0] playerAnswer,
  output wire [3:0] winner
);

  reg [3:0] playerAnswer;
  reg [3:0] winner;
  reg [3:0] buzzer;
  reg [4:0] count;

  always @(posedge clk or posedge reset) begin
    if (reset) begin
      playerAnswer <= 4'b0000;
      winner <= 4'b0000;
      buzzer <= 4'b0000;
      count <= 5'b00000;
    end else begin
      if (start) begin
        count <= 5'b10011; // 20秒倒计时
      end else begin
        if (count > 0) begin
          count <= count - 1;
        end else begin
          buzzer <= 4'b1111; // 20秒倒计时结束，无人抢答
        end
      end
    end
  end

  always @(posedge clk) begin
    if (start && count > 0 && buzzer == 4'b0000) begin
      if (playerAnswer == 4'b0000) begin
        if (player1_buzzer) begin
          playerAnswer <= 4'b0001;
          winner <= 4'b0001;
        end else if (player2_buzzer) begin
          playerAnswer <= 4'b0010;
          winner <= 4'b0010;
        end else if (player3_buzzer) begin
          playerAnswer <= 4'b0100;
          winner <= 4'b0100;
        end else if (player4_buzzer) begin
          playerAnswer <= 4'b1000;
          winner <= 4'b1000;
        end
      end
    end
  end

endmodule

该四人抢答器模块包含一个时钟输入（clk）、复位输入（reset）、开始抢答输入（start）、四个选手答案输出（playerAnswer）和获胜者输出（winner）。在开始抢答后的20秒倒计时期间，选手可以按下自己的抢答按钮（player1_buzzer、player2_buzzer、player3_buzzer、player4_buzzer），抢答器会记录第一个按下按钮的选手答案，并将其设置为获胜者。如果在倒计时结束前没有选手按下按钮，则获胜者将被设置为全1。