pic EEPROM读写问题

只看该作者 · 2009-11-14 16:54

最近学习到PIC单片机的EEPROM的读写操作，想在EEPROM的地址00H中写入20H这个数，然后再读出来到端口显示，但是操作后无反映，请大家帮忙.
;**************************************************
LIST  P=16f877
#INCLUDE <P16f877.INC>
__1EB9h;
;***************************************
ADDR equ    170h
VALUE equ    171h
COUNT1  equ    172h
COUNT2  equ    173h
EEDATA  equ    10ch
EECON1  equ    18ch
EECON2  equ    18dh
EEADR equ    10dh
INTCON  equ    0bh
PORTB equ    06h
TRISB equ    86h
;**************************************************
         ORG  000H
         NOP
         GOTO  MAIN
         ORG 0005H
MAIN:
         BANKSEL TRISB
         MOVLW  0x00
         MOVWF  TRISB
;**********************写EEPROM************************
WRITE:
         BANKSEL EECON1
         BTFSS EECON1,WR
         GOTO $-1
         BANKSEL EEADR
         MOVLW 00h
         MOVWF ADDR  ;EEPROM指定单元(00H)地址送ADDR
         MOVLW 20h
         MOVWF VALUE ;立即数送VALUE
         MOVF    ADDR,w
         MOVWF EEADR
         MOVF VALUE,w
         MOVWF EEDATA
         BANKSEL  EECON1
         BCF    EECON1,EEPGD
         BSF    EECON1,WREN
         BCF    INTCON,GIE
         MOVLW 0x55
         MOVWF EECON2
         MOVLW 0xAA
         MOVWF EECON2
         BSF    EECON1,WR
         BSF    INTCON,GIE
         BCF    EECON1,WREN
  HH:    BTFSS INTCON,EEIF  ;判断是否写EEPROM操作完成
         GOTO HH
  ;*****************读EEPROM**********************
READ:
         BANKSEL EEADR
         MOVF    ADDR,w ;把EEPROM的地址送EEADR (00H)
         MOVWF EEADR
         BANKSEL  EECON1
         BCF    EECON1,EEPGD
         BSF    EECON1,RD
         BANKSEL EEDATA
         MOVF    EEDATA,W ;取出上面写到EEPROM的数据(20H)
         BANKSEL PORTB
  YY    MOVWF    PORTB    ;送到PORTB口显示
         GOTO    YY

;*************************************
         END