数电课程设计——课设二：交通信号灯

一、实验内容

（1）十字路口有 x、y 方向两组交通信号灯，每组有红、黄、绿灯各一个；

（2）设计一个交通灯控制电路，模拟十字路口交通灯工作情况，红灯亮 35s，黄灯亮 5s，绿灯亮 30s；

（3）设系统时钟频率为 50MHz，要求用数码管显示计时结果；

（4）掌握 Verilog HDL 的状态机编程，红、黄、绿灯点亮转换用如下的状态转换图实现。

二、实验步骤

（1）编写代码

编写的.v顶层文件：


1.	module traffic(  
2.	    input clk,  
3.	    input rst,  
4.	      
5.	    output reg LEDR_Y,  
6.	    output reg LEDY_Y,  
7.	    output reg LEDG_Y,  
8.	    output reg LEDR_X,  
9.	    output reg LEDY_X,  
10.	    output reg LEDG_X  
11.	      
12.	);  
13.	parameter N = 25000000;  
14.	parameter S1 = 0;  
15.	parameter S2 = 1;  
16.	parameter S3 = 2;  
17.	parameter S4 = 3;  
18.	reg [25:0] count;  
19.	reg CLK_1Hz;  
20.	reg [2:0] cnt5;  
21.	reg [4:0] cnt30;  
22.	reg [1:0]state;//状态  
23.	  
24.	//生成1Hz时钟  
25.	always@(posedge clk or negedge rst)begin  
26.	if(!rst)begin  
27.	    count <= 0;  
28.	    CLK_1Hz <= 0;  
29.	end  
30.	else if(count<N-1)begin  
31.	    count <= count +1;  
32.	    CLK_1Hz <= CLK_1Hz;  
33.	end  
34.	else begin  
35.	    count <= 0;  
36.	    CLK_1Hz <= ~CLK_1Hz;  
37.	end  
38.	end  
39.	  
40.	//生成5进制计数器  
41.	always@(posedge CLK_1Hz or negedge rst)begin  
42.	if(!rst)begin  
43.	    cnt5 <= 0;  
44.	end  
45.	else if(cnt5<4)begin  
46.	    cnt5 <= cnt5 + 1;  
47.	end  
48.	else  
49.	    cnt5 <= 0;  
50.	end  
51.	  
52.	//生成30进制计数器  
53.	always@(posedge CLK_1Hz or negedge rst)begin  
54.	if(!rst)begin  
55.	    cnt30 <= 0;  
56.	end  
57.	else if(cnt30 < 29)begin  
58.	    cnt30 <= cnt30 + 1;  
59.	end  
60.	else  
61.	    cnt30 <= 0;  
62.	end  
63.	  
64.	//状态迁移  
65.	always@(posedge clk or negedge rst)begin  
66.	if(!rst)begin  
67.	    state <= 0;  
68.	end  
69.	else begin  
70.	    case(state)  
71.	      
72.	    S1:  
73.	        if(cnt30==29) state <= S3;  
74.	        else state <= S1;  
75.	    S2:  
76.	        if(cnt30==29) state <= S4;  
77.	        else state <= S2;  
78.	    S3:  
79.	        if(cnt5==4)   state <= S2;  
80.	        else state <= S3;  
81.	    S4:  
82.	        if(cnt5==4)   state <= S1;  
83.	        else state <= S4;  
84.	    default: state <= S1;  
85.	    endcase  
86.	end  
87.	end  
88.	  
89.	//状态  
90.	always@(posedge clk or negedge rst)begin  
91.	if(!rst)begin  //刚开始全灭  
92.	        LEDR_Y <= 0;  
93.	        LEDY_Y <= 0;   
94.	        LEDG_Y <= 0;  
95.	        LEDR_X <= 0;  
96.	        LEDY_X <= 0;  
97.	        LEDG_X <= 0;  
98.	end  
99.	else begin  
100.	    case(state)  
101.	    S1: begin   //Y方向绿灯亮，X方向红灯亮  
102.	        LEDR_Y <= 0;  
103.	        LEDY_Y <= 0;   
104.	        LEDG_Y <= 1;  
105.	        LEDR_X <= 1;  
106.	        LEDY_X <= 0;  
107.	        LEDG_X <= 0;  
108.	    end   
109.	    S2: begin   //X方向绿灯亮，Y方向红灯亮  
110.	        LEDR_Y <= 1;  
111.	        LEDY_Y <= 0;   
112.	        LEDG_Y <= 0;  
113.	        LEDR_X <= 0;  
114.	        LEDY_X <= 0;  
115.	        LEDG_X <= 1;  
116.	    end  
117.	    S3: begin   //X方向红灯亮，Y方向黄灯亮  
118.	        LEDR_Y <= 0;  
119.	        LEDY_Y <= 1;   
120.	        LEDG_Y <= 0;  
121.	        LEDR_X <= 1;  
122.	        LEDY_X <= 0;  
123.	        LEDG_X <= 0;  
124.	    end  
125.	    S4: begin   //X方向黄灯亮，Y方向红灯亮  
126.	        LEDR_Y <= 1;  
127.	        LEDY_Y <= 0;   
128.	        LEDG_Y <= 0;  
129.	        LEDR_X <= 0;  
130.	        LEDY_X <= 1;  
131.	        LEDG_X <= 0;  
132.	    end  
133.	    default: begin   //全灭  
134.	        LEDR_Y <= 0;  
135.	        LEDY_Y <= 0;   
136.	        LEDG_Y <= 0;  
137.	        LEDR_X <= 0;  
138.	        LEDY_X <= 0;  
139.	        LEDG_X <= 0;  
140.	    end  
141.	    endcase  
142.	end  
143.	  
144.	end  
145.	  
146.	endmodule 编写的textbench文件：
1.	`timescale 1 ns/ 1 ps  
2.	module traffic_tb();  
3.	// constants                                             
4.	// general purpose registers  
5.	  
6.	reg clk;  
7.	reg rst;  
8.	// wires                                                 
9.	wire LEDG_X;  
10.	wire LEDG_Y;  
11.	wire LEDR_X;  
12.	wire LEDR_Y;  
13.	wire LEDY_X;  
14.	wire LEDY_Y;  
15.	  
16.	// assign statements (if any)                            
17.	traffic i1 (  
18.	// port map - connection between master ports and signals/registers     
19.	    .LEDG_X(LEDG_X),  
20.	    .LEDG_Y(LEDG_Y),  
21.	    .LEDR_X(LEDR_X),  
22.	    .LEDR_Y(LEDR_Y),  
23.	    .LEDY_X(LEDY_X),  
24.	    .LEDY_Y(LEDY_Y),  
25.	    .clk(clk),  
26.	    .rst(rst)  
27.	);  
28.	initial                                                  
29.	begin                                                    
30.	     clk = 0;  
31.	      rst = 0;  
32.	      #100 rst = 1;  
33.	                       
34.	end    
35.	                                                    
36.	always   #10 clk <= ~clk;                                                
37.	                                              
38.	endmodule

编写的textbench文件：

`timescale 1 ns/ 1 ps  
module traffic_tb();  
// constants                                             
// general purpose registers  reg clk;  
reg rst;  
// wires                                                 
wire LEDG_X;  
wire LEDG_Y;  
wire LEDR_X;  
wire LEDR_Y;  
wire LEDY_X;  
wire LEDY_Y;  // assign statements (if any)                            
traffic i1 (  
// port map - connection between master ports and signals/registers     .LEDG_X(LEDG_X),  .LEDG_Y(LEDG_Y),  .LEDR_X(LEDR_X),  .LEDR_Y(LEDR_Y),  .LEDY_X(LEDY_X),  .LEDY_Y(LEDY_Y),  .clk(clk),  .rst(rst)  
);  
initial                                                  
begin                                                    clk = 0;  rst = 0;  #100 rst = 1;  end    always   #10 clk <= ~clk;                                                endmodule

三、实验结果

S1到S3的转换：