EP4CE6E2217按键控制流水灯

以下是EP4CE6E2217按键控制流水灯的Verilog代码示例：

module key_controlled_led (
    input wire clk,
    input wire rst,
    input wire key,
    output wire [3:0] led
);

reg [3:0] led_reg;
reg [3:0] led_next;

always @(posedge clk or posedge rst) begin
    if (rst) begin
        led_reg <= 4'b0000;
    end else begin
        led_reg <= led_next;
    end
end

always @(posedge clk) begin
    if (key) begin
        led_next <= led_reg << 1;
    end else begin
        led_next <= led_reg;
    end
end

assign led = led_reg;

endmodule

该代码实现了一个按键控制的流水灯。当按键按下时，流水灯向左移动一位，当按键松开时，流水灯保持不变。流水灯的状态保存在一个寄存器中，每个时钟周期根据按键的状态更新寄存器的值，并将其输出到LED灯。