2 Aug
2004
2 Aug
'04
5:31 a.m.
From: "John Honniball"
<coredump(a)gifford.co.uk>
Dwight K. Elvey wrote:
Hi John
That would most likely be part of what I'm looking for.
"42-pin quad in line" sounded like how they might describe
the spider chips. I suspect that this is what most of the
IC's are on this unit.
Dwight
>From: "John Honniball"
<coredump(a)gifford.co.uk>
>I have a book by Steve Money called "Microprocessor Data Book", and
>it lists three Rockwell 4-bit chips, the MM75, MM76 and MM78. They
>make up the PPS4/1 Series. Are they the ones you are interested in?
...
Hard to say. The chips I have all have inhouse
numbers on them.
It sure does sound like the right stuff though. The chips are
all 42 pin spider chips.
There's no detail about the packaging, but only one chip has 42 pins.
The MM78 (and MM78LA) is listed as "42-pin quad in line". That chip
has 2k of 8-bit ROM, 128x4 bit RAM and 31 I/O lines. Instructions
are 8 bits wide, but the ALU and memory are 4-bit. Maximum clock
frequency is 100kHz.
--
John Honniball
coredump(a)gifford.co.uk