On Mar 21, 23:04, Allison J Parent wrote:
> If I knew pinout I could find an industry part that would work save for
> pinout or package.
No offence, but if I can't get a drop-in replacement, I'd rather leave the
original as-is, and build my little expansion board. The idea was to
disable internal RAM (and perhaps ROM) and put a decoder on the expansion
connector (the old PETs have an internal expansion connector). The
expansion would carry up to 32K RAM, and one or more EPROMs holding
different versions of BASIC (the original doesn't work properly with
IEEE-488 disks and some other devices).
Anyway, here's the pinout:
MCS6550 1024 x 4 SRAM
A0 1 22 Vss (0V)
A1 2 21 CS1
A2 3 20 CS2
A3 4 19 ~CS3
A4 5 18 ~CS4
A5 6 17 Vdd (+5V)
phi2 7 16 D3
A6 8 15 D2
A7 9 14 D1
A8 10 13 D0
A9 11 12 R/~W
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
Received on Wed Mar 22 2000 - 03:31:01 GMT