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I guess you have to be born before 1960 to remember the KIM-1, SDK-85, SC/MP etc single-board computers.

I just repaired a very odd device from the 1977 timeframe with an unknown CPU. Most of the devices on the board are marked with "WE ***". The 4 RAM's are AMD AM9131BDC devices, the ROM is a "WE IV77" and the CPU (40 pins) is a "WE 179 212C" marked device. Peripherals are from the Intel family, e.g. the 8255 chip.

Other, small DIP-16 chips are marked "WE 177" and "WE 178".

The keyboard has a label "MACTUTOR" and I was able to step through a few instructions of the (random) RAM content. It is obviously a 8-bit CPU and has instruction length of 1, 2 or 3 bytes.

Any ideas????

Thanks for your help.

Regards,

Joerg

Quote:
I just repaired a very odd device from the 1977 timeframe with an unknown CPU. Most of the devices on the board are marked with "WE ***". The 4 RAM's are AMD AM9131BDC devices, the ROM is a "WE IV77" and the CPU (40 pins) is a "WE 179 212C" marked device. Peripherals are from the Intel family, e.g. the 8255 chip.

Other, small DIP-16 chips are marked "WE 177" and "WE 178".


Maybe Weitek (now Rockwell) made the chips? cannot seem to connect with ChipDocs at the moment, and UIowa just has WEITEK as the logo.

sdb

WE may stand for Western Electric.

Mac Tutor may refer to the Bell-Labs Mac-8 processor. Which would fit with Western Electric as the chip manufacturer.

A Google search revealed
http://minus-zero.net/mirrors/bitsavers.org/pdf/westernElectric/mac-8/

Hubert

Hubert,

Thank you so much - the three PDF's you digged out are the complete set of documentations for my MACTUTOR and I was already able to enter a small program.

Interesting 8-bit processor - I never heard about it. Very simple architecture and easy to understand.

Have a great weekend.

Regards,
Joerg

And it works like a charm - look at these bold chips:

Have a great weekend.

Regards,
Joerg

Joerg,

You are welcome.

Thank you for these nice picture.
The board looks like brand new!

Hubert

Hubert,

I programmed most of the early 8-bit CPU's, e.g. the 1802, 6502, 6800, 6301, SC/MP, 8085, Z-80 etc, but never heard about the MAC-8. It is an amazing simple but yet efficient design. It was, according to some PDF's I was no able to locate thanks to your help, design under the influence of - no, not drugs, UNIX.

I guess UNIX is pretty old ;-))

Regards,
Joerg

Hello Joerg,

Quote:
I guess UNIX is pretty old ;-))

I am older but not old. Therfore unix has to be pretty young :-) Developed in 1969 by Bell Labs, the manufaturer of your new toy.

Greetings,
max

Cool - I was already in Elementary School (Grundschule) in 1969 ;-))

Have a great weekend,

Joerg

Oh wow. It looks like someone ransacked my attic.
I'm suffering flashbacks from the HC-33/U crystal,
LM-323K TO-3 mug warmer, and ambivalence toward a
200:1 PCB to silicon die ratio. IIRC ceramic
DIP packages all but left the planet circa 1980.

I live with the regret of somewhere around 1985
tossing a KIM-1 board with the justification of
"who in their right mind would want this obsolete
junk?".

Joerg,

My 'fate' with this started with SDK80 from Intel, with a 8080, somewhere in 1976. Having only a serial TTY interface (8251), I repurposed an old portable TV-set into a CRT, with a keyboard build with single switches. The CRT digital electronics was build around a NS character ROM and a Siemens TV timing circuit (S187). A Lorenz Lo15 mechanical typewriter served his duties as a hardcopy printer. The most fun was to handcode all the routines necessary for ASCII <--> Baudot conversion, and to see them working. This set up was also used for some RTTY experiments, without the noisy typewriter.

I was also surprised to see that the MAC-8 development was driven by the suitability of this CPU for the C programming language. Had to write plenty of code in PL/M 80 and PLZ, C was not yet available at this time for the 8085 and Z80 CPUs.

Hubert

I always enjoy the recent tear-downs of various gadgets, e.g. the iPhone, reading "company xyz managed to stack an ARM9, a SDRAM and even a Flash memory in a so-and-so housing".

Well, more than 30 years ago (in 1979) the engineering school I attended purchased a bunch of the latest personal computers, the CBM 3032 series. Okay, just one CBM 3032 for the teachers, the students worked with the CBM 3016's.

One day, after school, I opened the hoods of both the 3032 (32k RAM) and 3016 (16k RAM) and recognized immediately: The fully loaded Commodore had two rows of 16k*1 dynamic RAM installed, the 3016 featured only one row and ONE ROW of neatly alligned 10 mm holes, drilled carefully into the PCB at the original places of the optional RAM's!

After studying both the layout and datasheets, I asked the other day my teacher, if I could borrow the CBM 3016 over a weekend for an "important project".
He agreed and I piggy-backed a set of MK4116 chips carefully one-to-one except the RAS and CAS pins, that I hand-wired to the left-overs of the traces ;-))

Wow - you should have seen his face after booting the CBM 3016 the following Monday to make sure the CBM is still working and he read the 32k RAM-Test message.

FYI: I earned a few hundered Deutsch Marks by updating all the CBM 3016's of this school and even another school.

OOPS: And later, collecting TI calculators, I learned that TI invented piggy-backing already in 1975 with the SR-51.
That's about the fuzz of stacked silicon ;-))

Regards,
Joerg

Quote:
The fully loaded Commodore had two rows of 16k*1 dynamic RAM installed, the 3016 featured only one row and ONE ROW of neatly alligned 10 mm holes, drilled carefully into the PCB at the original places of the optional RAM's!

Sounds about right for a Commodore "we sell computers to
the masses not the classes" maneuver.

Quote:
OOPS: And later, collecting TI calculators, I learned that TI invented piggy-backing already in 1975 with the SR-51.
That's about the fuzz of stacked silicon ;-))

My favorite recollection of dip piggybacking was the case
of the old CD4016 analog gates. This initial version had a
rather high "on" resistance but could be reduced by trivially
paralleling devices. To this end, a cohort once soldered
several together nested vertically totem pole style. He also
cut the head off a screw and cemented it onto the topmost
package. The fun then was to wait for someone to spot this
and inspect the bottom of the PCB to see if there was a nut
on the other side.