jiaotongdeng.v

交通灯程序

//date:2007/7/1  traffic lamp on the crossing
/* singal definition as follows:
clk: ??????
en?????
lampa???A??4????????lamp0?lamp3?????A???????????????
lampb???B??4????????lamp0?lamp3?????A???????????????
acount???A?????????????8??????2????
bcount???B?????????????8??????2????  */
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
            ared        <=8'b01010101;  //55s
            ayellow     <=8'b00000101;  //5s
            agreen      <=8'b01000000;  //40s
            aleft       <=8'b00010101;  //15s
            bred        <=8'b01100101;  //65s
            byellow     <=8'b00000101;  //5s
            bleft       <=8'b00010101;  //15s
            bgreen      <=8'b00110000;  //30s
        end
  
  
    assign  acount=numa;
    assign  bcount=numb;
    
    
    always @(posedge clk)
       begin
           if(en)
              begin
                if(!tempa) 
                  begin
                      tempa<=1;
                      
                      case(counta) //??????
                          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
                      if(numa>1)
                        if(numa[3:0])
                          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<=0;
             tempa<=0;
            end
    end
          
          
    always@(posedge clk)
      begin
         if(en)
           begin
               if(!tempa)
                 begin
                     tempb<=1;
                     case(countb)
                         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               //???
                      if(numb>1)
                        if(!numb[3:0])
                          begin
                              numb[3:0]<=9;
                              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