FPGA去抖 状态机

FPGA去抖状态机是一种用于消除输入信号中的抖动（即短时间内的信号波动）的状态机。它可以确保在输入信号稳定后，只产生一次有效的输出。

以下是一个简单的FPGA去抖状态机的示例代码：

module debounce (
  input wire clk,
  input wire button,
  output wire debounced_button
);

  // 定义状态
  typedef enum logic [1:0] {
    IDLE,
    PRESSED,
    RELEASED
  } state_t;

  // 定义状态机变量
  state_t state, next_state;

  // 定义输出变量
  logic debounced_button_reg, debounced_button_next;

  // 状态转换逻辑
  always_ff @(posedge clk) begin
    case (state)
      IDLE:
        if (button == 1'b1)
          next_state = PRESSED;
        else
          next_state = IDLE;
      PRESSED:
        if (button == 1'b0)
          next_state = RELEASED;
        else
          next_state = PRESSED;
      RELEASED:
        if (button == 1'b1)
          next_state = PRESSED;
        else
          next_state = IDLE;
    endcase
  end

  // 输出逻辑
  always_ff @(posedge clk) begin
    case (state)
      IDLE:
        debounced_button_next = 1'b0;
      PRESSED:
        debounced_button_next = 1'b0;
      RELEASED:
        debounced_button_next = 1'b1;
    endcase
  end

  // 状态和输出寄存器
  always_ff @(posedge clk) begin
    state <= next_state;
    debounced_button_reg <= debounced_button_next;
  end

  // 输出赋值
  assign debounced_button = debounced_button_reg;

endmodule

在上述代码中，我们定义了三个状态：IDLE（空闲状态）、PRESSED（按下状态）和RELEASED（释放状态）。状态机根据输入信号button的变化来切换状态，并根据当前状态生成输出信号debounced_button。