下降沿触发的事件----控制led灯亮灭(edge test)
防止持续触摸 才让led持续点亮;
采用register打拍的方式确定 输入信号touch_flag的 negedge;
module touch_ctrl_led(
input wire sys_clk,
input wire sys_rst_n,
input wire touch_key,
output reg led
);
//touch_key1将输入signal同步到sys_clk下;
//touch_key2对touch_key1打一拍;
reg touch_key1;
reg touch_key2;
wire touch_flag;
always@(posedge sys_clk or negedge sys_rst_n)
if(!sys_rst_n)begin
touch_key1 <=1'b1;
touch_key2 <=1'b1;
end
else begin
touch_key1 <= touch_key;
touch_key2 <=touch_key1;
end
//组合逻辑采集边沿
assign touch_flag =(