On Sep 10, 23:26, Paul Williams wrote:
> I'm looking at dumping the ROMs from a VT100 board, but I'm having
> trouble finding pinouts of the ROMs.
>
> The VT100 FMPS says that locations E40, E45, E52 and E56 on the basic
> board are 8316E 2Kx8 ROMs. However, the schematics don't show the
> designations for all 24 pins. The online Chip Directory doesn't contain
> the pinout for the 8316 either.
>
> My PROM Programmer will handle 2716 EPROMs, which the Chip Dir. does
> contain a pinout for, and looks compatible with the 8316. I'd be tempted
> to try dumping one of them, were it not for the fact that E45 on my
> board is actually labelled "AM9218CPC", the pinout for which is also
> absent from the Chip Dir.
>
> Could anyone please tell me definitively whether the 8316, 9218 and 2716
> are pin-compatible?
Nearly, providing you're referring to the 5-volt-only 2716. The polarity
of the chip selects is mask-programmable on the 8316. I don't know which
way DEC used for the VT100, but the way they usually did it was CS1 and CS2
(pins 18 and 20) active-low with CS3 active high (pin 21, Vpp on a 2716,
which is usually at +5V for reading). The alternative is CS1, CS2, and CS3
all active-low.
So if you are reading DEC 8316's on a programmer, set it for 2716, and if
it reads as if empty, bend out pin 21 and ground it.
I'd be interested to know which VT100 ROMs you have, since I collect such
things. The number that matters is something like 23-031E2 (23- means ROM,
031 is the code number, and E2 means 16K bit). The standard VT100 ROMs are
031 (or 061), 032, 033, and 034, but there are lots of variants. I have
images (and original ROMs) of 061, 032, 033, 034 but I'd like to get any
others to add to the archive.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Mon Sep 10 2001 - 19:07:36 BST