The Nabu Games Board

In 1981 I worked for a company called Nabu Manufacturing based in Ottawa.  At Nabu I managed a department of two and we designed and created an S-100 compatible PC board.  We used the Z80 processor and the TI 9918 video chip - state-of-the-art technology at that time.

Together with Dave Weins, my very capable assistant, we wrote the specification.  Dave did the hardware development, and I wrote a CP/M-compatible operating system that booted off a cable modem and development tools for Nabu's games programmers.  Today I marvel at Dave's patience, since I was only 25 years old at the time, and Dave had just turned 40.

Here are some pictures we took at the end of the project:

The Dolch logic analyzer was a joy to use.  We could find bugs in real-time.


This is the board that Dave made - I learned a lot about SSI and MSI logic design from him.


Dave was usually a hard working guy.  We got along really well.


This is what the development system looked like.  We connected a Volker-Craig VT-100 clone to the serial port, and a TV to the NTSC output of the TI 9918 video chip.  Notice the 8 inch floppy drives.


We used an extension board so we could attach probes to the S100 card that we were working on.  I think the Z80 chip ran at 1 MHz, and the S100 bus ran slower than that, so a six inch extension on the bus didn't wreak the havok that this would cause with today's clock speeds


Tracking down a bug on the Dolch logic analyser often meant attaching probes to some chips and studying the rising and falling edges of the waveforms.  We also decided where to put trim capacitors according to the voltage 'bounce' shown on the scope.