用verilog写一个4x4矩阵键盘的代码

下面是一个简单的4x4矩阵键盘的Verilog代码：

module matrix_keypad(input wire [3:0] row, input wire [3:0] col, output reg [15:0] key);

reg [3:0] row_sel;
reg [3:0] col_sel;
wire [3:0] row_scan;
wire [3:0] col_scan;

// 行扫描器，将行选择信号轮流设为高电平
always @ (posedge clk) begin
    row_sel <= row_sel + 1;
    if (row_sel == 4) row_sel <= 0;
end

// 列扫描器，检测列扫描信号是否为高电平
always @ (posedge clk) begin
    col_sel <= col_sel + 1;
    if (col_sel == 4) col_sel <= 0;
end

// 矩阵键盘行扫描
assign row_scan = {~row[0], ~row[1], ~row[2], ~row[3]};
// 矩阵键盘列扫描
assign col_scan = {col[0], col[1], col[2], col[3]};

// 检测按键是否按下
always @ (posedge clk) begin
    if ((row_scan & (1 << row_sel)) && (col_scan & (1 << col_sel))) begin
        key <= (row_sel << 2) | col_sel; // 将按下的按键编码输出
    end
end

endmodule

该代码使用一个row信号和一个col信号来读取4x4矩阵键盘的输入。它将键码编码为16位输出信号，并在检测到按键按下时输出该信号。该代码还包括行扫描器和列扫描器，它们轮流选择行和列进行扫描。