使用verilog写一个uart驱动

下面是一个简单的 Verilog 代码，实现了一个基本的 UART 驱动，包括接收和发送功能：

module uart (
    input clk,
    input rst,
    input rx,
    output tx
);

reg [7:0] data;
reg [2:0] state;
reg [3:0] count;
reg tx_busy;

parameter IDLE = 0, START = 1, DATA = 2, STOP = 3;

always @(posedge clk) begin
    if (rst) begin
        state <= IDLE;
        count <= 0;
        tx_busy <= 0;
        tx <= 1;
    end else begin
        case (state)
            IDLE: begin
                if (!rx) begin
                    state <= START;
                    count <= 0;
                end else if (tx_busy) begin
                    tx <= 0;
                end else begin
                    tx <= 1;
                end
            end
            START: begin
                if (count < 8) begin
                    data[count] <= rx;
                    count <= count + 1;
                end else begin
                    state <= DATA;
                    count <= 0;
                end
            end
            DATA: begin
                if (count < 8) begin
                    count <= count + 1;
                end else begin
                    state <= STOP;
                    count <= 0;
                end
            end
            STOP: begin
                if (count < 2) begin
                    count <= count + 1;
                end else begin
                    state <= IDLE;
                    count <= 0;
                    tx_busy <= 0;
                end
            end
        endcase
    end
end

always @(posedge clk) begin
    if (rst) begin
        data <= 0;
    end else begin
        case (state)
            IDLE: begin
                if (tx_busy) begin
                    tx <= 0;
                end
            end
            START: begin
                tx <= 0;
            end
            DATA: begin
                tx <= data[count];
            end
            STOP: begin
                tx <= 1;
            end
        endcase
    end
end

always @(posedge clk) begin
    if (rst) begin
        tx_busy <= 0;
    end else begin
        case (state)
            START: begin
                tx_busy <= 1;
            end
            STOP: begin
                tx_busy <= 0;
            end
        endcase
    end
end

endmodule

此代码没有经过完整测试，仅供参考。你需要根据具体的需求进行修改和调整。