Hi
I have followed the instructions for writing to the internal EEPROM
throroughly - I tried copying the code from the PIC datasheet, have
tried code I found on piclist, but I cannot get a successful result. My
code I use to read and write is at the end of the message.
EEPROM_WRITE_TEST sets up the address and data and then calls
EEPROM_WRITE to write to EEPROM. EEPROM_READ_TEST sets up address and
then calls EEPROM_READ.  I am using a PIC16F877 and the IceBreaker is my
incircuit debugger. The debugger allows me to read and write straight to
EEPROM and I have tried setting values in EEPROM addresses but
EEPROM_READ always returns 0xFF (although when I read them with the
debugger it returns the correct value, so im sure there is nothing wrong
with the EEPROM).  Can anyone please help me here and tell me what Im
doing wrong - is there something else I need to do other than run this
code to access the EEPROM?
Thanks in advance..
 - Michael

EEPROM_WRITE_TEST
        bsf STATUS,RP1          ; Bank 2
        bcf STATUS,RP0          ;
        movlw 0x00                      ; Address to write to
        movwf EEADR                     ; Move into EEPROM address reg
        movlw 0xAA                      ; Some test data
        movwf EEDATA            ; Save data to write
        call EEPROM_WRITE               ; Write to EEPROM
        bcf STATUS,RP1
        return


EEPROM_WRITE
        bcf PIR2,EEIF           ; Clear any previous EEPROM interrupt
        bsf STATUS,RP0          ; Bank 3
        bcf INTCON,GIE          ; Disable interrupts
        bcf EECON1, EEPGD               ; Select data EEPROM
        bsf EECON1, WREN                ; Enable writes
        movlw 0x55                      ; 0x55 and 0xAA
        movwf EECON2            ;  are codes which turn
        movlw 0xAA                      ;  on the EEPROM access
        movwf EECON2            ;
        bsf EECON1,WR           ; Begin write
        bsf INTCON,GIE          ; Turn on global interrupt mask
        bcf EECON1,WREN         ; Disable writes again
        bcf STATUS,RP0          ;
        bcf STATUS,RP1          ; Back to bank 0
        btfss PIR2,EEIF         ; Wait for write complete
        goto $ - 1                      ; interrupt before continuing
        bcf PIR2,EEIF           ; Clear interrupt
        bsf STATUS,RP1          ; Bank 2 again
        return


EEPROM_READ_TEST
        movlw 0x00                      ; Address to read from
        call EEPROM_READ
        return

EEPROM_READ
        bsf STATUS,RP1          ;
        bcf STATUS,RP0          ; Bank 2
        movwf EEADR                     ; Set up address
        bsf STATUS,RP0          ; Bank 3
        bcf EECON1,EEPGD                ; Select data EEPROM access
        bsf EECON1,RD           ; Enable EEPROM read
        bcf STATUS,RP0          ; Back to bank 2
        movf EEDATA,w           ; Get data
        return

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