【iCore1S 双核心板_FPGA】例程二：GPIO输入实验——识别按键输入

module KEY(
input CLK_12M,
input FPGA_KEY,
output FPGA_LEDR,
output FPGA_LEDG,
output FPGA_LEDB
);
//----------------------rst_n-----------------------//
//产生复位信号
reg rst_n;
reg [3:0]cnt_rst;

always@(posedge CLK_12M)
if(cnt_rst==4'd10)
begin
rst_n <= 1'd1;
cnt_rst <= 4'd10;
end
else cnt_rst <= cnt_rst + 1'd1;
//-----------------------KEY_CLK--------------------//
//将按键的按下与松开转换为KEY_CLK,按下后松开为上升沿
reg KEY_CLK;
reg [7:0]cnt_key0;
reg [7:0]cnt_key1;
always@(posedge CLK_12M or negedge rst_n )
begin
if(!rst_n)
begin
KEY_CLK <= 1'd0;
cnt_key0 <= 8'd0;
cnt_key1 <= 8'd0;
end
else if(!FPGA_KEY)
begin
cnt_key0 <= cnt_key0 + 1'd1;
if(cnt_key0==8'd200)//消抖
begin

if(!FPGA_KEY)
begin
KEY_CLK <= 1'd0;
cnt_key0 <= 8'd0;
end
end
end
else if(FPGA_KEY)
begin
cnt_key1 <= cnt_key1 + 1'd1;
if(cnt_key1==8'd200)//消抖
begin
if(FPGA_KEY)
begin
KEY_CLK <= 1'd1;
cnt_key1 <= 8'd0;
end
end
end
end
//-----------------------led-------------------------//
reg [1:0]led_state;
reg ledr,ledg,ledb;

always@(posedge KEY_CLK or negedge rst_n)
begin
if(!rst_n)
begin
led_state <= -2'd1;//初始化使灯熄灭
ledr <= 1'd1;
ledg <= 1'd1;
ledb <= 1'd1;
end
else
begin
led_state <= led_state + 1'd1;
if(led_state > 2'd2)
begin
led_state <= 2'd0;
end
case(led_state)
2'd0:            //红灯亮
begin
ledr <= 1'd0;
ledg <= 1'd1;
ledb <= 1'd1;
end
2'd1:            //绿灯亮
begin
ledr <= 1'd1;
ledg <= 1'd0;
ledb <= 1'd1;
end
2'd2:            //蓝灯亮
begin
ledr <= 1'd1;
ledg <= 1'd1;
ledb <= 1'd0;
end
default :    //灯熄灭
begin
ledr <= 1'd1;
ledg <= 1'd1;
ledb <= 1'd1;
end
endcase
end
end

assign FPGA_LEDR = ledr;
assign FPGA_LEDG = ledg;
assign FPGA_LEDB = ledb;

//--------------------endmodule------------------//
endmodule