eproms

[Mike Rolica]

Thanks.  Duh, never thought to check out data sheet on hc11f1 to see what
speed was.  Hey guess what, also found a didgikey cat in my desk hutch,
already in can dollars!!!
Mike Rolica
EXT. 260
 :-)


	-----Original Message-----
	From:	Marteney, Steven J. [SMTP:smarteney at xlvision.com]
	Sent:	Wednesday, November 10, 1999 1:52 PM
	To:	gmecm at efi332.eng.ohio-state.edu
	Subject:	RE: eproms

	There shouldn't be a problem with using a 27c512; however, this chip
will
	have at least 2 more address bits that need be connected somewhere.
	(Grounding them will make it a 27c128.)

	Also be careful of pinout.  I'm not directly familiar with pin outs,
but a
	lot of times the smaller PROM will be in the same package as the
bigger with
	the two extra address lines marked as no connects.  If not, you need
to
	re-map the pins correctly with jumper wires or whatever.  You've
just got to
	verify that the extra two address lines get back to the
microcontroller and
	the uC will support addressing that much memory.

	Don't see a problem with using the E2PROM.  Again, pinouts need to
be
	checked and the read write times should be the same or faster.
Again, if
	the 165 ECM uses an HC11 it shouldn't have a bus cycle any where
near the
	capabilities of a classic EPROM or E2PROM.  Research!  Data sheets
tell the
	story!

	As far erasing an E2PROM, there are higher voltages (ie 12V) that
need to be
	applied to certain pins for a specified time and sometimes block
protect
	addresses that need to be programmed to allow it to be erased.  If
you want
	to do it in the car, be prpeared to have to add some extra
circuitry.
	Again, read the datasheets!

	Steve

	-----Original Message-----
	From: Mike Rolica [mailto:mrolica at meridian-mag.com]
	Sent: Wednesday, November 10, 1999 1:02 PM
	To: Gmecm (E-mail)
	Subject: eproms


	OK, so I have a 87 165 ecm with a 27c128 eprom.  Now a couple of
questions.
	Can I huse a 27c512 eprom cause it has extra room?  What would I
have to do
	to use this one and/ or why can't I?  Second I have asked this
question
	before... but can I use a eeprom instead (so I don't have to erase
it uv all
	the time) ?
	Lastly  where would I find some blank eproms ?
	Mike Rolica
	EXT. 260
	 :-)