Newsgroups: comp.robotics
Path: brunix!uunet!stanford.edu!snorkelwacker.mit.edu!news.media.mit.edu!fredm
From: fredm@media.mit.edu (Fred G Martin)
Subject: MC68HC11 trivia
Message-ID: <1992Aug30.135517.28340@news.media.mit.edu>
Sender: news@news.media.mit.edu (USENET News System)
Organization: MIT Media Laboratory
References: <1992Aug29.220411.3485@hemlock.cray.com>
Date: Sun, 30 Aug 1992 13:55:17 GMT
Lines: 24

In article <1992Aug29.220411.3485@hemlock.cray.com> kilian@cray.com
(Alan Kilian) writes: 

+----------------------------------------------------------------------------+
| PART NUMBER | EPROM | ROM | EEPROM | RAM |  Comments
+----------------------------------------------------------------------------+
| MC68HC11A8  |  ---  |  8K |   512  | 256 | Family built around this device   
| MC68HC11A1  |  ---  | --- |   512  | 256 | 'A8 with ROM disabled             
| MC68HC11A0  |  ---  | --- |   ---  | 256 | 'A8 with ROM and EEPROM disabled  
etc.


Motorola won't tell you this, but versions of the 6811 that don't have
EEPROM (for example, the mc68hc11a0) actually *have* the EEPROM on the
chip die, and the die didn't pass inspection, so the chip was packaged
as "6811 without EEPROM."

This means that you can pop the CONFIG register to turn on the EEPROM,
and voila, the EEPROM is there!  I've tried this on a number of
different chips and it does work.  Of course, you shouldn't use this
EEPROM for mission-critical applications, because it's not up to spec,
but for a lot of hobbyist applications, it'll work just fine.

	- Fred
