Jay West wrote:
> Since the blank chips are nigh impossible to find anymore... is it possible
> to use something like a PIC chip on a small DIP carrier card, that could be
> plugged into an existing loader rom or microcode rom socket and function
> just like the "real thing" to the system?
You wouldn't use a PIC chip for something like this. A PIC would be
used in a microcontroller-type application, where program-controlled
behaviour is required. To replace a ROM, we could simply use another
ROM (or PROM, EPROM, EEPROM, Flash ROM, etc.) with a pinout adaptor.
People are already doing this for PROMs in mobile radios. These PROMs
are in fact the same chips as one finds in a PDP-11 for booting (M9312)
and for storing the 8008 firmware in an 11/34 console card. The
PROMs in question are 82S131, 74S571 or Am27S13 types (512x8). I have
some blanks here to fix a console card, as it happens.
Scroll down here:
http://www.open.org/~blenderm/syntorx/legacy.html
to the section headed "EPROM Conversion" to read about the PROM
replacements for Syntor radios. And see this page:
http://www.open.org/~blenderm/syntorx/legacyeprom.html
for photos of a completed adaptor.
Do you know the chip numbers and/or specs for the ROMs you wish to
emulate?
--
John Honniball
coredump_at_gifford.co.uk
Received on Thu Jul 29 2004 - 17:01:58 BST