Thanks! I'll mess with my code taking these considerations into account.

Harold


On Tue, 16 Jan 2001 12:06:20 -0700 Richard Ottosen <rottosen@IDCOMM.COM>
writes:
> Harold:
> I would that invoking the read while writing will _immediatly_
> change
> from writing to reading. Very bad.
>
> Also, be aware that changing the EEPROM data or address while
> writing
> will cause the EEPROM hardware to start writing with the original
> data/address and finish writing with the new data/address. Also very
> bad.
>
> If you want to put the check for EEPROM ready at the start of the
> EEPROM
> subroutine then you must use temporary variables to hold the data
> and
> address until the EEPROM is ready to accept the updating of the
> EEPROM
> data and address registers.
>
> I hope this makes sense. If not, I can give an example.
>
>
> -- Rich
>
>
>
> Harold M Hallikainen wrote:
> >
> >         In my code, I've done the check for end of write on the
> way in to the
> > write routine instead of on the way out, figuring that I could get
> other
> > stuff done before I get stuck in a loop waiting for the eeprom
> write to
> > finish. As I think about it more, though, are reads inhibited
> until the
> > write cycle is complete? This is the case with the 2816 EEPROM
> with which
> > I am more familiar. So, maybe it IS a good idea to wait for the
> write to
> > finish before doing anything that might try to read the eerpom.
> >
> > Harold
> >
> > On Tue, 16 Jan 2001 09:20:01 -0500 Drew Vassallo
> <snurple@HOTMAIL.COM>
> > writes:
> > > You may have also forgotten another line, I can't remember
> exactly if
> > > it's
> > > required - I haven't used it in a while.  Try this:
> > >
> > >                 bsf     STATUS, RP0     ; select Bank1 for EECON
> > > access
> > >                 bcf     INTCON, GIE     ; disable interrupts
> > > temporarily
> > >                 bsf     EECON1, WREN    ; enable EEPROM write
> > >                 movlw   0x55
> > >                 movwf   EECON2
> > >                 movlw   0xAA
> > >                 movwf   EECON2
> > >                 bsf     EECON1, WR      ; write values to EE
> > >                 bsf     INTCON, GIE     ; reenable interrupts
> > >                 bcf     EECON1, WREN    ; disable EEPROM write
> > > Waitforflag
> > >                 btfss   EECON1, EEIF    ; poll flag bit
> > >                 goto    Waitforflag
> > >                 bcf     EECON1, EEIF    ; write cycle complete
> > >                 bcf     STATUS, RP0     ; leave Bank0 active by
> > > default
> > >                 return
> > >
> > > --Andrew
> > >
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