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