eproms

[Marteney, Steven J.]

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
 :-)