触摸按键控制LED

1. 触摸按键： 电阻式，电容式(主流)，红外感应式，表面声波式
2. 代码
   input: sys_clk, sys_rst_n, key
   output: led
   
   FPGA判断上升沿是通过将原信号延迟，再对比获取上升沿

src/touch_led.v

module touch_led(
	input 						sys_clk,
	input 						sys_rst_n,
	input 					 	touch_key,

	output 		reg		led		
);

reg touch_key_d0;
reg touch_key_d1;

wire pos_touch_key;
assign pos_touch_key = ~touch_key_d1 & touch_key_d0;//采上升沿

//打两拍，采集上升沿
always @(posedge sys_clk or negedge sys_rst_n) begin
	if(!sys_rst_n) begin
		touch_key_d0 <= 1'd0;
		touch_key_d1 <= 1'd0;
	end
	else begin
		touch_key_d0 <= touch_key; //打两拍
		touch_key_d1 <= touch_key_d0 ;
	end
end

//led信号反转
always @(posedge sys_clk or negedge sys_rst_n) begin
	if(!sys_rst_n) 
		led <= 1'd1;
	else if(pos_touch_key)//上升沿
		led <= ~led;
	else
		led <= led;
end
endmodule

3.仿真代码

sim/tb/tb_touch_led.v

`timescale 1ns/1ns

module tb_touch_led();
parameter CLK_PERIOD = 20;//时钟周期

reg 				sys_clk;//需要被赋值，所以定义为reg类型
reg 				sys_rst_n;
reg 	 			touch_key;

wire  			led; //不会被赋值，所以定义为wire型。注意：如果是assign连续赋值，则是对wire类型赋值

initial begin
	sys_clk <= 1'b0;
	sys_rst_n <= 1'b0;
	touch_key <= 1'b0;
	#200  //延时200ns
	sys_rst_n <= 1'b1;

	//模拟按键按下/释放
	#2000
	touch_key <= 1'b1;
	#2000
	touch_key <= 1'b0;
end

always #(CLK_PERIOD/2) sys_clk = ~sys_clk; //每隔10ns取反一次，时间周期20ns

touch_led u_touch_led(
	.sys_clk 				(sys_clk),
	.sys_rst_n 			(sys_rst_n),
	.touch_key 			(touch_key),
	.led 					(led))
endmodule