时序图


代码
key_filter.v文件
module key_filter
(
input wire sys_clk ,
input wire sys_rst_n ,
input wire key_in ,
output reg key_flag
);
reg [19:0] cnt;
always@(posedge sys_clk or negedge sys_rst_n)
if(sys_rst_n == 1'b0)
cnt <= 20'd0;
else if(key_in == 1'b1)
cnt <= 20'd0;
else if(cnt == 20'd999_999