A51 MACRO ASSEMBLER  8255_2_                                                              07/25/2006 13:26:46 PAGE     1


MACRO ASSEMBLER A51 V8.00
OBJECT MODULE PLACED IN 8255(2).OBJ
ASSEMBLER INVOKED BY: e:\Program Files\Keil\C51\BIN\A51.EXE 8255(2).asm SET(SMALL) DEBUG EP

LOC  OBJ            LINE     SOURCE

0000                   1                     ORG             00H
  7CFF                 2     PORTA   EQU             7CFFH                   ;A口
  7DFF                 3     PORTB   EQU             7DFFH                   ;B口
  7EFF                 4     PORTC   EQU             7EFFH                   ;C口
  7FFF                 5     CADDR   EQU             7FFFH                   ;控制字地址
0000 802E              6                     SJMP    START
0030                   7                     ORG             30H
0030 7482              8     START:  MOV             A,#82H                  ;方式0,PA,PC輸出，PB輸入
0032 907FFF            9                     MOV             DPTR,#CADDR
0035 F0               10                     MOVX    @ DPTR,A
0036 907DFF           11                     MOV     DPTR,#PORTB
0039 E0               12                     MOVX    A,@ DPTR        ;讀入B口
003A 907CFF           13                     MOV     DPTR,#PORTA
003D F0               14                     MOVX    @DPTR,A                 ;輸出到A口
003E 1143             15             CALL    DELAY 
0040 020030           16                     LJMP    START
0043 7E00             17     DELAY:  MOV             R6,#0
0045 7F00             18             MOV             R7,#0
0047                  19     DELAYLOOP:
0047 DEFE             20                     DJNZ    R6,DELAYLOOP
0049 DFFC             21                     DJNZ    R7,DELAYLOOP
004B 22               22                     RET
                      23                     END
A51 MACRO ASSEMBLER  8255_2_                                                              07/25/2006 13:26:46 PAGE     2

SYMBOL TABLE LISTING
------ ----- -------


N A M E             T Y P E  V A L U E   ATTRIBUTES

CADDR. . . . . . .  N NUMB   7FFFH   A   
DELAY. . . . . . .  C ADDR   0043H   A   
DELAYLOOP. . . . .  C ADDR   0047H   A   
PORTA. . . . . . .  N NUMB   7CFFH   A   
PORTB. . . . . . .  N NUMB   7DFFH   A   
PORTC. . . . . . .  N NUMB   7EFFH   A   
START. . . . . . .  C ADDR   0030H   A   


REGISTER BANK(S) USED: 0 

ASSEMBLY COMPLETE.  0 WARNING(S), 0 ERROR(S)