HP41C with Rp Pico attached

[MeindertKuipers]

This is a really cool project, and thanks for sharing. I like how you implement the extra display and the HP41 bus tracer. I have implemented an HP41 bus tracer myself and did not expect that a microcontroller would be able to keep up with the HP41 bus speed while dumping the results over USB in real time. But with a 2 core controller things are now different.
The Pico looks like a good candidate for a new generation of HP41 peripherals, although I doubt that it will fit in a module housing with all the level shifters. Also powering the RP2040 from the HP41 battery will be a challenge. But then again I do not mind a box external to the calculator with its own power source.