       ORG 0000H
START: MOV P1,#0FH
 LOOP:JNB P1.0,AA
      JB P1.1, BB
       MOV P1,#3FH       £»¿ª×óµÆ£¬¹ØÓÒµÆ
       LCALL DELAY
       LJMP LOOP
BB:MOV P1,#0FH
       LCALL DELAY
       SJMP LOOP
AA:    JB P1.1,CC
MOV P1,#0FH
LCALL DELAY
LJMP LOOP
CC:    MOV P1,#0CFH        £»¿ªÓÒµÆ£¬¹Ø×óµÆ
       LCALL DELAY
       LJMP LOOP
DELAY: MOV  R5,#0FFH
LP:    MOV  R6,#0FFH
D0:    DJNZ  R6,D0
       DJNZ  R5,LP
       RET
       END
