基于Verilog有限状态机实现的LED按键灯项目

项目实现功能

       通过按键控制，模仿市面上的台灯开关，即通过按键控制灯的状态。该项目假设led按键灯共有四种状态，分别是红灯，黄灯，蓝灯。 通过按键按下，改变当前led灯的状态。例：当前为熄灭状态，按下按键后红灯亮起。

项目环境

１.vivado 2019.1
２.xilinx Fpga AX7035开发板

具体代码

下面展示具体实现代码

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: 
// 
// Create Date: 2020/04/19 15:50:32
// Design Name: 
// Module Name: Led
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//////////////////////////////////////////////////////////////////////////////////


module Led(
     input key,
     input reset,
     output reg [2:0]led
    );
    parameter   Led_off=2'b00;
    parameter   Led_red=2'b01;
    parameter   Led_yellow=2'b10;
    parameter   Led_blue=2'b11;
    reg [1:0]current_state;
    reg [1:0]next_state;
    always @(posedge key  or negedge reset)
	      begin
	        if(~reset)
	                begin
	                current_state <= Led_off;
	               // led <= 3'b000;
	                end
	        else         
	                current_state <= next_state;  
	      $display ("curr_state is %d",current_state);
	      end
    always@( current_state or reset )
	    begin
	               begin
	                     case (current_state)
	                        Led_off:　　　next_state = Led_red;
	                        Led_red:　　　next_state = Led_yellow;
	                        Led_yellow:　next_state = Led_blue;
	                        Led_blue:　　 next_state = Led_off;
	                        default: 　　 next_state = Led_off;
	                     endcase
	               end
	     end     
     always @(current_state or reset )
	     begin
	           case( current_state)
	                 Led_off : led = 3'b111;
	                 Led_red : led = 3'b110;
	                 Led_yellow : led = 3'b101;
	                 Led_blue: led = 3'b011;
	             default: led =3'b111;    
	           endcase
	     end
endmodule

仿真代码及波形图

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: 
// 
// Create Date: 2020/04/19 16:10:38
// Design Name: 
// Module Name: Sim_led
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//////////////////////////////////////////////////////////////////////////////////


module Sim_led;
        reg key,reset;
        wire [2:0]led;
        Led l1(key,reset,led);
      
       initial
          begin
            key=0;
            reset= 0;           
            #10 reset=1;
            
            #50 reset =0;
            
            #100 reset = 1;
            #200 $stop;
          end

        
         always #10  key = ~key;
endmodule

约束文件代码

	############## NET - IOSTANDARD ##################
	
set_property CFGBVS VCCO [current_design]
set_property CONFIG_VOLTAGE 3.3 [current_design]

#############SPI Configurate Setting##################

set_property BITSTREAM.CONFIG.SPI_BUSWIDTH 4 [current_design] 
set_property CONFIG_MODE SPIx4 [current_design] 
set_property BITSTREAM.CONFIG.CONFIGRATE 50 [current_design] 

############## clock and reset define##################

#create_clock -period 20 [get_ports {clk}]
#set_property IOSTANDARD LVCMOS33 [get_ports {clk}]
#set_property PACKAGE_PIN Y18 [get_ports {clk}]

set_property IOSTANDARD LVCMOS33 [get_ports {reset}]
set_property PACKAGE_PIN F20 [get_ports {reset}]

#############LED Setting#############################

set_property PACKAGE_PIN F19 [get_ports {led[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[0]}]

set_property PACKAGE_PIN E21 [get_ports {led[1]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[1]}]

set_property PACKAGE_PIN D20 [get_ports {led[2]}]
set_property IOSTANDARD LVCMOS33 [get_ports {led[2]}]

############## key define##############################

set_property PACKAGE_PIN M13 [get_ports key]
set_property IOSTANDARD LVCMOS33 [get_ports key]
set_property CLOCK_DEDICATED_ROUTE FALSE [get_nets key]

过程中遇到的错误及解决方法

[Place 30-574] Poor placement for routing between an IO pin and BUFG.
If this sub optimal condition is acceptable for this design, you may use the CLOCK_DEDICATED_ROUTE constraint in the .xdc file to demote this message to a WARNING. However, the use of this override is highly discouraged. These examples can be used directly in the .xdc file to override this clock rule.
< set_property CLOCK_DEDICATED_ROUTE FALSE [get_nets key_IBUF] >

key_IBUF_inst (IBUF.O) is locked to IOB_X0Y60
and key_IBUF_BUFG_inst (BUFG.I) is provisionally placed by clockplacer on BUFGCTRL_X0Y31

经过查阅资料，发现是该项目并未使用fpga开发板原置的内部晶振作为时钟，而是通过按键模拟时钟信号导致.

解决方法：
在约束文件中加入如下语句：

set_property CLOCK_DEDICATED_ROUTE FALSE [get_nets key]

上板实验

由于fpga板并没有多种颜色的灯，故使用多个led灯进行模拟。
具体图片如下（视频无法上传）：