交通灯控制器

/* 信号定义与说明：

CLK： 为同步时钟；

EN： 使能信号，为1 的话，则控制器开始工作；

LAMPA： 控制A 方向四盏灯的亮灭；其中，LAMPA0~LAMPA3，分别控制A 方向的

左拐灯、绿灯、黄灯和红灯；

LAMPB： 控制B 方向四盏灯的亮灭；其中，LAMPB0 ~ LAMPB3，分别控制B 方向的

左拐灯、绿灯、黄灯和红灯；

ACOUNT： 用于A 方向灯的时间显示，8 位，可驱动两个数码管；

BCOUNT： 用于B 方向灯的时间显示，8 位，可驱动两个数码管。 */

module traffic(CLK,EN,LAMPA,LAMPB,ACOUNT,BCOUNT);

output[7:0] ACOUNT,BCOUNT;

output[3:0] LAMPA,LAMPB;

input CLK,EN;

reg[7:0] numa,numb;

reg tempa,tempb;

reg[2:0] counta,countb;

reg[7:0] ared,ayellow,agreen,aleft,bred,byellow,bgreen,bleft;

reg[3:0] LAMPA,LAMPB;

always @(EN)

if(!EN)

begin //设置各种灯的计数器的预置数

ared <=8'd55; //55 秒

ayellow <=8'd5; //5 秒

agreen <=8'd40; //40 秒

aleft <=8'd15; //15 秒

bred <=8'd65; //65 秒

byellow <=8'd5; //5 秒

bleft <=8'd15; //15 秒

bgreen <=8'd30; //30 秒

end

assign ACOUNT=numa;

assign BCOUNT=numb;

always @(posedge CLK) //该进程控制A 方向的四种灯

begin

if(EN)

begin

if(!tempa)

begin

tempa<=1;

case(counta) //控制亮灯的顺序

0: begin numa<=agreen; LAMPA<=2; counta<=1; end

1: begin numa<=ayellow; LAMPA<=4; counta<=2; end

2: begin numa<=aleft; LAMPA<=1; counta<=3; end

3: begin numa<=ayellow; LAMPA<=4; counta<=4; end

4: begin numa<=ared; LAMPA<=8; counta<=0; end

default: LAMPA<=8;

endcase

end

else begin //倒计时

if(numa>1)

if(numa[3:0]==0) begin

numa[3:0]<=4'b1001;

numa[7:4]<=numa[7:4]-1;

end

else numa[3:0]<=numa[3:0]-1;

if (numa==2) tempa<=0;

end

end

else begin

LAMPA<=4'b1000;

counta<=0; tempa<=0;

end

end

always @(posedge CLK) //该进程控制B 方向的四种灯

begin

if (EN)

begin

if(!tempb)

begin

tempb<=1;

case (countb) //控制亮灯的顺序

0: begin numb<=bred; LAMPB<=8; countb<=1; end

1: begin numb<=bgreen; LAMPB<=2; countb<=2; end

2: begin numb<=byellow; LAMPB<=4; countb<=3; end

3: begin numb<=bleft; LAMPB<=1; countb<=4; end

4: begin numb<=byellow; LAMPB<=4; countb<=0; end

default: LAMPB<=8;

endcase

end

else

begin //倒计时

if(numb>1)

if(!numb[3:0]) begin

numb[3:0]<=9;

numb[7:4]<=numb[7:4]-1;

end

else numb[3:0]<=numb[3:0]-1;

if(numb==2) tempb<=0;

end

end

else begin

LAMPB<=4'b1000;

tempb<=0; countb<=0;

end

end

endmodule