Update Schematic and PCB

A project log for My CP/M Version 1A

I decided to do a minor upgrade to My CP/M (Version 1). Swap RST6.5 for RST7.5 and increase the FRAM disk capacity from 32k to 256k.

agp.cooperagp.cooper 07/07/2020 at 05:580 Comments

Updated the Schematic and PCB

Well I did update the schematic and PCB but found I had done that some time ago.

So I sent the PCB off for manufacture.

Here is the schematic:

CP/M Firmware

I will have to collect the work I did on the first version and update the "cbios.asm" for the new FRAM size etc.

I will also have to collect the programs I want to put on the "Flash Disks". Previously  I wrote a C program to do this. However, writing the hex code to flash has to be in 16kb passes as the Nano can only hold about this much. Not really problem as hex code can be added incrementally.

The Flash Programmer

Here is the Flash Programmer:

It is set up for either an AT29C256 or a W29C020.

Note: When flashing these chips I use software protections to avoid the chips losing their contents due to accidental writes (during debugging).

Here is the assembled Flash Programmer (with the old My CP/M computer):