Playing with HP2640B

Brent Hilpert bhilpert at
Tue Dec 5 13:44:11 CST 2017

On 2017-Dec-05, at 9:14 AM, Mattis Lind via cctalk wrote:
> Looking more into this document revelas that it covers three boards
> 02640-60009, 02640-60088 and 02640-60112.
> Now I had the idea of dumping the character ROM as well. But what is a AMD
> 27S82? I cannot really find a datasheet online. From the schematics above
> it looks not too much off from standard 2716 EPROM with pin 19 (A10) as E3
> , pin 21 (VPP)  as /E1. But my Data I/O 29B does not seem to be compatible
> with 27S82 and as  pin 21 is active low it gives that a 2716 setting in the
> programmer (reader) won't work.
> Does the 27S82 have any equivalents that I could look up instead in the
> device list?

FWIW, 27S82 is listed in the 1982 IC Master as
	AM27S82M:   TTL 1024*8 ROM, 275nS access, OC outputs, 24 pin, 5V supply

So half the size of a 2716.
The book lists PROMs and ROMs separately, so it was probably mask-programmed.
(M would be for mil temp going by other AMD numbers.)

More information about the cctalk mailing list