开发板环境：vivado2017.4

开发板：Zedboard 芯片型号：xc7z020clg484-1

本章主要使用用verilog编写一个按键检测程序，按一次按键LED亮一次，依次点亮八个LED灯

按键工程

 按键检测代码

`timescale 1ns / 1ps
//
// Company: 
// Engineer: 
// 
// Create Date: 2022/02/26 12:48:48
// Design Name: 
// Module Name: key_test
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//


module key_test(
input           clock,//100M
input           reset,//SW0
input           key_in,//BTNC
output  [7:0]   led//LED0~LED7

    );
   
     
    
    reg         key_in_r1;
    reg         key_in_r2;
    wire        key_in_flag;
    
    reg         key_out;
    reg         key_out_r1; 
    reg         key_out_r2;
    
    reg [19:0]  cnt;
    reg [7:0]   led_reg;   
    wire        key_out_flag;
     
    
    always @ (posedge clock, negedge reset)
            if(!reset) 
                key_in_r1 <= 1'b1;
            else        
                key_in_r1 <= key_in;
     
    
    always @ (posedge clock, negedge reset)
            if(!reset) 
                key_in_r2 <= 1'b1;
            else        
                key_in_r2 <= key_in_r1;
    
    assign key_in_flag = (!key_in_r2 & key_in_r1); 
    
    always @ (posedge clock, negedge reset)
            if(!reset)
                cnt <= 20'h0;
            else if(key_in_flag)
                cnt <= 20'h0;
            else
                cnt <= cnt + 1'b1;
    
    always @ (posedge clock, negedge reset)
            if(!reset)
                key_out <= 1'b1;
            else if(cnt == 20'hfffff)            
                key_out <= key_in;
     
    
    always @ (posedge clock, negedge reset)
            if(!reset)
                key_out_r1 <= 1'b1;
            else
                key_out_r1 <= key_out;
    
    always @ (posedge clock, negedge reset)
            if(!reset)
                key_out_r2 <= 1'b1;
            else
                key_out_r2 <= key_out_r1;
    
assign  key_out_flag =   (!key_out_r2 && key_out_r1);  

//点亮LED
    always@(posedge clock or negedge reset)begin
            if(!reset)    
                led_reg    <=  8'b00000001;
            else if(key_out_flag)begin
                if(led_reg == 8'b10000000)
                    led_reg    <=  8'b00000001;
                else    
                    led_reg    <=  led_reg<<1;
            end        
end

assign  led =   led_reg;
               
endmodule

按键检测约束文件

set_property PACKAGE_PIN T22 [get_ports {led[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[0]}]
set_property PACKAGE_PIN T21 [get_ports {led[1]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[1]}]
set_property PACKAGE_PIN U22 [get_ports {led[2]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[2]}]
set_property PACKAGE_PIN U21 [get_ports {led[3]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[3]}]
set_property PACKAGE_PIN V22 [get_ports {led[4]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[4]}]
set_property PACKAGE_PIN W22 [get_ports {led[5]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[5]}]
set_property PACKAGE_PIN U19 [get_ports {led[6]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[6]}]
set_property PACKAGE_PIN U14 [get_ports {led[7]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[7]}]
set_property PACKAGE_PIN Y9 [get_ports clock]
set_property IOSTANDARD LVCMOS33 [get_ports clock]
set_property PACKAGE_PIN F22 [get_ports reset]
set_property IOSTANDARD LVCMOS33 [get_ports reset]


set_property PACKAGE_PIN P16 [get_ports key_in]
set_property IOSTANDARD LVCMOS33 [get_ports key_in]

使用的按键

 

将reset打到下面不然会一直复位，然后按key按键，注意key按键默认没有按的时候是低电平，按键按下就会输入高电平，所以和大多少的按键相反，写程序注意按键上升沿检测按键

开发板上电后第一个led灯亮

按一下按键，第二个灯亮

再按一下按键，第三个灯亮，每次按键都是依次点亮led,如果按了八次就会重新从第一个灯开始亮起