HP-25 DIY with Z80

[eshazen]

I needed a new one for my office, and for variety I decided to use VFD displays.
It has a new power supply PCB at the back to provide the 1.2V @ ~1A and 25V for the VFDs and handle power sequencing.

I used Microchip HV5812 drivers for the VFDs which was quite straightforward.
All docs updated on github: https://github.com/eshazen/retro-25