Yet another TMS9900 computer

I came across a reference to a “Cortex” computer that was based on the TMS9900 from TI (same as in the TI 99/4A.) I had to go digging, and so far information is scant. But I found this:
And here is the kit manual.
I’m not sure about Cortex II vs. just plain Cortex. It seems the original was written up in ETI magazine in 1982. The Cortex II seems to be a kit offered by Powertran Cybernetics. More digging required!
EDIT: This appears to be a scan of the original article.


That’s a pretty interesting memory architecture, using DRAM and having DRAM shadowing of the ROM (so that writes to ROM addresses transparently fall through to DRAM). The 8-bit memory bus is a bit unfortunate, although I’m sure the cost-effectiveness at the time made it worthwhile. The TMS9995’s on-board register file may make up for that (compared to the TMS9900’s off-board registers) in practice.

The TMS9929 (9928 for those of us using 60 Hz displays) is a pretty amazing video chip, as well! As Quinn Dunki recently summed up the 8-bit era machines (paraphrasing), their bizarre architectures make sense if you think of them primarily as a video generation system, with a CPU bolted on the side. The powerful one-chip video capabilities of the TMS9918/19/28/29 allowed the computer to do more computing and less graphics production.

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Found a site apparently dedicated to the Cortex:

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