jtdkz.vhd

课程设计《交通灯控制的设计》

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
ENTITY JTDKZ IS
   PORT(CLK,SB:IN STD_LOGIC;
        MR,MY0,MG0,BR,BY0,BG0:OUT STD_LOGIC);
END JTDKZ;
ARCHITECTURE art OF JTDKZ IS
  TYPE STATE_TYPE IS(A,B,C,D);
  SIGNAL STATE:STATE_TYPE;
  BEGIN
  CNT:PROCESS(SB,CLK)IS
  VARIABLE S:INTEGER RANGE 1 TO 45;
  BEGIN
    IF(CLK'EVENT AND CLK='1')THEN
    CASE STATE IS
    WHEN A=>MR<='0';MY0<='0';MG0<='1';BR<='1';BY0<='0';BG0<='0';    
     IF SB='1'THEN  
      IF S=45 THEN STATE<=B;S:=1;
      ELSE STATE<=A;S:=S+1;
      END IF;
     ELSIF SB='0'THEN STATE<=A;
         IF S=45 THEN S:=S;
         ELSE S:=S+1;
         END IF;
     END IF;
    WHEN B=>MR<='0';MY0<='1';MG0<='0';BR<='1';BY0<='0';BG0<='0';
        IF S=5 THEN STATE<=C;S:=1;
        ELSE STATE<=B;S:=S+1;
        END IF;
    WHEN C=>MR<='1';MY0<='0';MG0<='0';BR<='0';BY0<='0';BG0<='1';
    
      IF S=25 THEN STATE<=D;S:=1;
      ELSE STATE<=C;S:=S+1;
      END IF;
    
    WHEN D=>MR<='1';MY0<='0';MG0<='0';BR<='0';BY0<='1';BG0<='0';
       IF S=5 THEN STATE<=A;S:=1;
       ELSE STATE<=D;S:=S+1;
       END IF;
     END CASE;
     END IF;   
  END PROCESS CNT;
END art;