uart串口Verilog发送模块仿真代码

以下是一个基本的UART串口发送模块的Verilog仿真代码：

module uart_tx(
  input clk,
  input rst,
  input [7:0] data_in,
  input start,
  output reg tx_done,
  output reg [3:0] state,
  output reg tx_out
);

parameter IDLE = 4'b0000;
parameter START_BIT = 4'b0001;
parameter DATA_BITS = 4'b0010;
parameter STOP_BIT = 4'b0011;

reg [3:0] next_state;

always @(*) begin
  case(state)
    IDLE: begin
      if(start) begin
        next_state = START_BIT;
        tx_out = 0;
      end else begin
        next_state = IDLE;
        tx_out = 1;
      end
    end
    START_BIT: begin
      next_state = DATA_BITS;
      tx_out = 0;
    end
    DATA_BITS: begin
      next_state = STOP_BIT;
      tx_out = data_in[0];
      data_in = {data_in[6:0], 1'b0};
    end
    STOP_BIT: begin
      next_state = IDLE;
      tx_out = 1;
      tx_done = 1;
    end
    default: next_state = IDLE;
  endcase
end

always @(posedge clk or posedge rst) begin
  if(rst) begin
    state <= IDLE;
    tx_out <= 1;
    tx_done <= 0;
  end else begin
    state <= next_state;
    tx_done <= 0;
    if(state == STOP_BIT) begin
      tx_done <= 1;
    end
  end
end

endmodule

此代码实现了一个基本的UART发送模块，包括状态机、数据位、起始位和停止位的处理。在仿真时，您需要提供一个测试平台来生成时钟和数据输入信号，并检查输出信号是否正确。