10 Sep
2001
10 Sep
'01
12:07 p.m.
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