I've been having problems programming the internal EE area on the 16C84.
My code follows the sequence 0xaa, 0x55 etc as described in the data
book.  I'm using a picmaster emulator system.

When using the emulator it all works fine, the data is stored and
retrieved as would be expected.  When I burn the chip it fails to work.
I can easily tell if the programmed values are within the correct range
from the response of the target application.
I also use a Universal Xeltec programmer, with this I can pre-program
values into the EE that I know are in the correct range.  When I do this
it all works fine.  That is the chip is reading the values out of the
eeprom properly.  When I let it write the new values they are random in
value but written over the correct address range, the rest stay zero.

Originally I was using looping until the complete flag had come up.
I've also tried simply waiting the required delay but I still get
incorrect values.  Also tried different chips to see if the ee area on
the chip itself was at fault, unlikely I feel, no luck there either all
three chips behaved the same.

Here is a portion of the code in two parts macro and eewrite subroutine.


{macro write_ee}

WRITE_EE        MACRO   ADR, DAT

                        movlw           ADR
                        movwf           EEADR
                        movf            DAT,W
                        movwf           EEDATA
                        call            Write_EEProm

                        ENDM

{Subroutine Write_EEprom}

Write_EEProm:          PAGE1                    ;Macro, move to page 1
                       bcf     EECON1-0x80,WRERR
                       bcf     EECON1-0x80,EEIF
                       movlw   0x55
                       movwf   EECON2-0x80
                       movlw   0xAA
                       movwf   EECON2-0x80
                       bsf     EECON1-0x80,WR

Wait_EEProm:           btfss   EECON1-0x80,EEIF
                       goto    Wait_EEProm
                       bcf     EECON1-0x80,WREN
                       PAGE0                    ;Macro, back to page 0
return


I would appreciate any suggestions you could offer.

Many Thanks

Shane

Email: goweed@hotmail.com

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