I purposely left out all comments I had made, so when
the code was looked at my potentially false thoughts
on what was happening wouldn t interfere with other
people s views (sort of like proofreading your own
papers for grammar errors).  Without my comments, it
forces you to look at each segment and figure out what
is going on, and what I may have been trying to do.

But thanks for the advice!

--Nick


--- Olin Lathrop <olin_piclist@EMBEDINC.COM> wrote:
> > Danger, Will Robinson. PIR1 is in bank 0, you're
> in bank 1.
>
> I see Bob has already pointed out some bank
> switching problems.
>
> I deal with this issue by never "manually" messing
> with the RP0 and RP1 bits
> in status.  Check out the DBANKIF and related macros
> in STD.INS.ASPIC at
> http://www.embedinc.com/pic.  However, the biggest
> problem I see with your
> code is lack of comments.  When you ask 2000 people
> to look at your code,
> you owe it to them (if not to yourself) to at least
> explain what you thought
> you were doing.  Often you will find your own
> problem after being forced to
> explain your logic to someone else.  Here's how I
> would write the snippet.
> Warning, totally untested code:
>
> ;
> ;   Set all the EEPROM locations from 0 to 7F to the
> value FF.
> ;
> ;   This code assumes interrupts are disabled.
> ;
>          dbankif eedata
>          movlw   h'FF'       ;set the data value to
> write to all locations
>          movwf   eedata
>          dbankif eeadr
>          clrf    eeadr       ;init next EEPROM
> address to write to
>          dbankif eecon1
>          bsf     eecon1, wren ;enable writing to the
> EEPROM
>
> nextadr  unbank              ;back each new byte to
> write to the EEPROM
>          dbankif pir1
>          bcf     pir1, eeif  ;reset flag to EEPROM
> write not completed yet
>
>          dbankif eecon2
>          movlw   h'55'       ;do the special
> sequence to allow EEPROM write
>          movwf   eecon2
>          movlw   h'AA'
>          movwf   eecon2
>          dbankif eecon1
>          bsf     eecon1, wr  ;start the write
>
>          dbankif pir1
> wait_write                   ;back here until the
> EEPROM write completes
>          clrwdt              ;tell the watchdog we
> are still alive
>          btfss   pir1, eeif  ;the write has
> completed ?
>          goto    wait_write  ;no, go back and check
> again
>
>          dbankif eeadr
>          movf    eeadr, w    ;get the current EEPROM
> address
>          xorwf   h'7F'       ;compare to the last
> address
>          skip_nz             ;not just wrote to the
> last address ?
>          goto    done_write  ;yes, all done
>          incf    eeadr       ;advance to the next
> address
>          goto    nextadr     ;back to write to this
> new address
> done_write unbank            ;all done clearing
> EEPROM
>
>
>
>
********************************************************************
> Olin Lathrop, embedded systems consultant in
> Littleton Massachusetts
> (978) 742-9014, olin@embedinc.com,
> http://www.embedinc.com
>
> --
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>
>


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