verilog写超声波测距的数码管显示

首先，需要通过超声波传感器测量距离，并将其转换为数字信号，然后通过数码管进行显示。下面是一个简单的Verilog代码示例：

module ultrasonic_distance(
    input clk,
    input trig,
    output reg [3:0] seg,
    output reg [3:0] dig
);

reg [15:0] counter;
reg measure;
reg [3:0] distance;

always @(posedge clk) begin
    if (counter < 16'd50000) begin
        counter <= counter + 1;
    end else begin
        counter <= 0;
        measure <= 1;
    end
end

always @(posedge clk) begin
    if (trig && !measure) begin
        counter <= 0;
        measure <= 1;
    end
end

always @(posedge clk) begin
    if (measure) begin
        measure <= 0;
        counter <= 0;
        distance <= counter / 58; // 转换为厘米
    end
end

always @(posedge clk) begin
    case (distance)
        0: seg = 4'b0011; // 显示0
        1: seg = 4'b0001; // 显示1
        2: seg = 4'b0101; // 显示2
        3: seg = 4'b0100; // 显示3
        4: seg = 4'b0110; // 显示4
        5: seg = 4'b0110; // 显示5
        6: seg = 4'b0111; // 显示6
        7: seg = 4'b0004; // 显示7
        8: seg = 4'b0111; // 显示8
        9: seg = 4'b0110; // 显示9
        default: seg = 4'b1111; // 显示空
    endcase
end

always @(posedge clk) begin
    dig <= 4'b1110; // 第一个数码管
    #100;
    dig <= 4'b1101; // 第二个数码管
    #100;
    dig <= 4'b1011; // 第三个数码管
    #100;
    dig <= 4'b0111; // 第四个数码管
end

endmodule

该模块有一个时钟输入 `clk`，一个触发输入 `trig`，和一个四位数码管显示输出。它使用一个计数器来测量超声波传感器返回的脉冲宽度，然后将其转换为距离（单位是厘米），并通过数码管进行显示。每个数码管的显示切换时间间隔为 100 个时钟周期。