to.asm

定时器的应用

BADDR  EQU  30H
SADDR  EQU  31H
       ORG  0000H
       LJMP START
       ORG  000BH
       LJMP INT0
       ORG  0030H
LEDMAP:
       DB  3FH,18H,76H,7CH,59H,6DH,6FH,38H
START: MOV TMOD,#81H
       MOV TH0,#0F6H
       MOV TL0,#0EFH
       SETB  EA
       SETB  ET0
       SETB  TR0
       LCALL CHUSHI
MAIN:  LCALL  SHOW
       LJMP  MAIN
SHOW:  LCALL  INCODE
       MOV    P2,BADDR
       MOV    P1,SADDR
       RET
INCODE:  MOV  BADDR,R1
         MOV  A,R2
         MOV  DPTR,#LEDMAP
         MOVC A,@A+DPTR
         MOV  SADDR,A
         RET
INT0:    CLR   TR0
         MOV   TH0,#0F6H
         MOV   TL0,#0EFH
         SETB  TR0
         INC   R1
         INC   R2
         CJNE  R1,#08H,EXIT
         LCALL CHUSHI
EXIT:    RETI
CHUSHI:  MOV   R1,#00H
         MOV   R2,#00H
         RET