Hi all,

In a PIC16F627 application I recently developed, I am having a code-hang=20
problem.  My best diagnosis so far, is that the code is getting stuck in =
the=20
EEPROM write routine [code posted at the end of this email] which is call=
ed=20
from a main code loop.  Interrupt processing seems to be working fine sti=
ll,=20
even though this main loop is locked up.

In the write routine, I'm waiting on the EEIF flag to be set, indicating =
that=20
the write operation is complete, but I'm guessing that this is where it's=
=20
getting stuck.

The EEPROM writes happen in groups of 5 (all calling this routine), and I=
'm=20
not verifying that the write operation was successful by checking the act=
ual=20
value saved (at least, not yet).  I'm also not using a watchdog timer yet=
=2E =20
The 2 other interrupts are TMR0 which updates the multiplexed display, an=
d=20
TMR2 which checks for and processes an external signal.

Any idea what could be going wrong here?=20

Cheers,
-Neil.



;-----------------------------------------------------------------
; Write data to EEPROM (location supplied in W, data in E_DATA)
;-----------------------------------------------------------------

WriteEEData:
=09bcf=09PIR1,EEIF=09; Reset write-complete flag

=09bsf=09STATUS,RP0=09; Bank 1
=09movwf=09EEADR
=09bcf=09STATUS,RP0=09; Bank 0
=09movf=09E_DATA,W=09; Get data to be stored
=09bcf=09PIR1,EEIF=09; Ensure interrupt flag off while in bank 0
=09bsf=09STATUS,RP0=09; Bank 1
=09movwf=09EEDATA

=09bsf=09EECON1,WREN=09; Enable writes
=09bcf=09INTCON,GIE=09; Disable interrupts
=09movlw=09H'55'=09=09; Special seq
=09movwf=09EECON2=09=09; ...
=09movlw=09H'AA'=09=09; ...
=09movwf=09EECON2=09=09; ...
=09bsf=09EECON1,WR=09; Start write operation
=09bcf=09EECON1,WREN=09; Disable writes
=09bcf=09STATUS,RP0=09; Bank to bank 0

=09bsf=09INTCON,GIE=09; Re-enable interrupts

WriteEEWait:
=09btfss=09PIR1,EEIF=09; Check EEIF flag for write completion
=09goto=09WriteEEWait

WriteEEDataDone:
=09return

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