I got stuck in trying to debug what went wrong in the Fuzix boot.

To combat that frustration I've been working on learning Kicad 6 properly, while also trying to design a PZ1 PCB around the Raspberry Pi Pico instead of the Teensy.

The Pico is really cheap and readily available but has too few gpio pins, so I use five 74-chips to expand the usage of the available pins. This should work well but requires more cycles on the Pico.

Kicad 6 is really nice to work with, though the bus/wire concept in the schematic capture could really be more streamlined and documented better. I also got Freerouter running, so the resulting PCB is a 75x100mm 4-layer card. Compared to the commercial package I used before 2000, this is a very powerful, quick and easy tool to use!

I'll do a few more inspections spread out over a few days before I feel ready to order a PCB.

This revision of PZ1 has a proper 65C02 CPU and 512KiB SRAM with the Pico acting as glue logic and 6502-I/O. The 74-chips are gpio-expanders to the Pico.