Originally Posted by hap
Yes, I'm more than OK with this topic being about other antique microcontrollers too.

(articles keep calling them "calculator chips", but seriously, they're the 1st gen. of MCUs)

I agree, on both counts. smile

This guy also agrees that B6001 is a PPS-4/1 microcontroller, while others disagree.
Keep clicking "next in thread" for more fun smile

We may never know until someone traces out the circuit to compare with the PPS-4/1 pinouts, or decaps a standard PPS-4/1 to compare.