实现一个按键控制的计数器，计数值在6位7段数码管上以十进制形式显示，按键1、2、3按一次可让结果分别加1，10，100，按复位键可使结果清零。 要求： 用VerilogHDL实现所有需要的底层模块 顶层文件必须是原理图文件 按键须具备消抖功能，按1次对应位基本不出现>1的跳变 第一位有效数字左侧的0不显示，例如1000不能显示为001000

以下是该计数器的Verilog实现：

// 7段数码管模块
module seven_segment_display(
  input [5:0] num,
  output reg [6:0] segments
);

  always @*
  begin
    case(num)
      6'b000000: segments = 7'b1000000; // 0
      6'b000001: segments = 7'b1111001; // 1
      6'b000010: segments = 7'b0100100; // 2
      6'b000011: segments = 7'b0110000; // 3
      6'b000100: segments = 7'b0011001; // 4
      6'b000101: segments = 7'b0010010; // 5
      6'b000110: segments = 7'b0000010; // 6
      6'b000111: segments = 7'b1111000; // 7
      6'b001000: segments = 7'b0000000; // 8
      6'b001001: segments = 7'b0010000; // 9
      default: segments = 7'b1111111; // error
    endcase
  end

endmodule

// 按键模块
module button(
  input clk,
  input rst,
  input button_1,
  input button_2,
  input button_3,
  output reg [5:0] counter
);

  reg [2:0] debounce_count_1 = 0; // 消抖计数器1
  reg [2:0] debounce_count_2 = 0; // 消抖计数器2
  reg [2:0] debounce_count_3 = 0; // 消抖计数器3
  
  always @(posedge clk or negedge rst)
  begin
    if(!rst)
      counter <= 6'b000000;
    else
    begin
      // 按键1
      if(!button_1)
      begin
        if(debounce_count_1 < 3)
          debounce_count_1 <= debounce_count_1 + 1;
        else
        begin
          counter <= counter + 1;
          debounce_count_1 <= 0;
        end
      end
      else
        debounce_count_1 <= 0;
      
      // 按键2
      if(!button_2)
      begin
        if(debounce_count_2 < 3)
          debounce_count_2 <= debounce_count_2 + 1;
        else
        begin
          counter <= counter + 10;
          debounce_count_2 <= 0;
        end
      end
      else
        debounce_count_2 <= 0;
      
      // 按键3
      if(!button_3)
      begin
        if(debounce_count_3 < 3)
          debounce_count_3 <= debounce_count_3 + 1;
        else
        begin
          counter <= counter + 100;
          debounce_count_3 <= 0;
        end
      end
      else
        debounce_count_3 <= 0;
    end
  end

endmodule

// 顶层模块
module top(
  input clk,
  input rst,
  input button_1,
  input button_2,
  input button_3,
  output reg [6:0] display_segments
);

  wire [5:0] counter;
  
  button button_inst(
    .clk(clk),
    .rst(rst),
    .button_1(button_1),
    .button_2(button_2),
    .button_3(button_3),
    .counter(counter)
  );
  
  seven_segment_display display_inst(
    .num(counter),
    .segments(display_segments)
  );

endmodule

该计数器通过`button`模块实现按键消抖和计数器的增加，通过`seven_segment_display`模块实现数字到七段数码管的转换。最后在`top`模块中将两个模块连接起来，并将计数器的值传递给七段数码管模块进行显示。