Forums

External RAM and EEPROM

Started by chuc...@yahoo.com August 9, 2006
Hello everyone, I have a question regarding the M68HC11EBVU. Its the old
board from the 90's with the mc68hc11e1 chip in place of the e9. I've
installed a 32k SRAM chip and a 128k EEPROM chip on the wirewrap side and
I've been wondering on how to interface it correctly so that I can program the external EEPROM via the MCU. I've never used any other software such as
pcbug11 etc. How can I do this? Can the buffalo monitor or some other
software accomplish this? If anyone could help out Id appreciate it very
much. THANKS!!!
I once put a 32K NVRAM on ports A and B on a 711E9 based EVBU. It was
for archiving data so I just accessed it through the ports while in
single chip mode. BUFFALO let me drive it with my internal EEPROM/EPROM
residing program. Note: although I basically wired it up like the pink
book showed (including latch) for expanded multiplexed mode, I was
driving it in single chip mode.

Let me know if you have any questions.

Emmett Redd Ph.D. mailto:E...@missouristate.edu
Associate Professor (417)836-5221
Department of Physics, Astronomy, and Materials Science
Missouri State University Fax (417)836-6226
901 SOUTH NATIONAL Dept (417)836-5131
SPRINGFIELD, MO 65897 USA

"When I was a child, I spake as a child, I understood as a child, I
thought as a child: but when I became a man, I put away childish
things," like being too embarrassed to ask questions which my peers
might think as stupid.

________________________________

From: m... [mailto:m...]
On Behalf Of c...@yahoo.com
Sent: Wednesday, August 09, 2006 8:13 PM
To: m...
Subject: [m68HC11] External RAM and EEPROM

Hello everyone, I have a question regarding the M68HC11EBVU. Its
the old
board from the 90's with the mc68hc11e1 chip in place of the e9.
I've
installed a 32k SRAM chip and a 128k EEPROM chip on the wirewrap
side and
I've been wondering on how to interface it correctly so that I
can program the external EEPROM via the MCU. I've never used any other
software such as
pcbug11 etc. How can I do this? Can the buffalo monitor or some
other
software accomplish this? If anyone could help out Id appreciate
it very
much. THANKS!!!
Thanks for the information on the single chip mode with ports A and BI didnt know about that!
Although, I am trying to access both the 32K SRAM chip and 32K (of the 128K
EEPROM) chip in multiplexed expanded mode. I already have the 573 latch in
place for [A0:A7] and everything is wired up. I used the "MD 8000 FFFF"
command in BUFFALO to check if I can access the EEPROM, and the last set of
code that I had burned on there with a EEPROM programmer is still there,
which hopefully means the chip is still in good condition. However, I would
like to know how to do on-board external EEPROM burning with this setup. I
don't intend on using this unit as a full time programmer, I just want to be
able to update the code on the EEPROM without an expensive chip programmer
or other external hardware. And of course, I would like to be able to run my code from the external EEPROM as well. I know a large number of people use
this sort of setup, with some sort of third party software to burn their
EEPROMs without a trip to the programmer, it has something to do with
bootstrap mode and the INTERNAL EEPROM. If you guys have any information
on the sort of software I should be using, or the jumper settings on my
board, or any tips or tricks would be greatly appreciated.

THANKS AGAIN!