写一个基于FPGA的4x4矩阵键盘数码管的代码

下面是一个基于FPGA的4x4矩阵键盘数码管的代码：

module keypad_display(
  input clk,
  input [3:0] row,
  output reg [6:0] led,
  output reg [6:0] seg,
  output reg [3:0] col
);

reg [15:0] key;
reg [3:0] key_buf;
reg [2:0] disp_cnt;
reg [3:0] disp_sel;
reg [6:0] seg_data;
reg [6:0] seg_table [0:9] = {7'b0000001, 7'b1001111, 7'b0010010, 7'b0000110, 7'b1001100, 7'b0100100, 7'b0100000, 7'b0001111, 7'b0000000, 7'b0000100};

assign col = 4'b1110;

always @(posedge clk) begin
  key <= {key[11:0], row};

  if (key[15:12] != 4'b1111 && key_buf == 4'b1111) begin
    case (key[15:12])
      4'b1110: led <= led + 1;
      4'b1101: led <= led - 1;
      4'b1011: disp_cnt <= disp_cnt + 1;
      4'b0111: disp_cnt <= disp_cnt - 1;
    endcase
  end

  key_buf <= key[15:12];

  if (disp_sel == 3) begin
    seg_data <= seg_table[disp_cnt[1:0]];
  end else begin
    seg_data <= seg_table[disp_cnt[3:2]];
  end

  case (disp_sel)
    3: seg = {seg_data, 7'b0000001};
    2: seg = {seg_data, 7'b0000010};
    1: seg = {seg_data, 7'b0000100};
    0: seg = {seg_data, 7'b0001000};
  endcase

  if (disp_sel == 3) begin
    col = 4'b1101;
  end else begin
    col = {col[2:0], 1'b0};
  end

  disp_sel <= disp_sel + 1;

end

endmodule

上述代码实现了一个简单的4x4矩阵键盘和数码管的组合。键盘连接在FPGA板上的GPIO口，数码管连接在FPGA板上的七段数码管驱动芯片上。按下键盘上的不同按钮时，数码管会显示不同的数字。