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Posted: Mon May 15, 2023 5:03 am
by MicroCoreLabs
Hi Everyone,

For those who are testing and developing new ROMs for the NABU I would like to share my EPROM Emulator project.

Here is a WordPress blog where I introduced this project a few years ago: ... -emulator/

This EPROM emulator uses a Teensy 4.0 and a very small PCB to emulate an EPROM of up to 64 KB. The ROM contents are stored in a simple array and the 600 Mhz Teensy has more than enough raw speed to sample the address lines and drive the data signals in a loop. The PCBs can be made for under five US dollars and the Teensy 4.0 at this point is under $25, which makes this emulator among one of the cheapest solutions available.

It works great with my NABU, and the version of the code I uploaded to GitHub contains every NABU ROM which I could find.

The GitHub project can be found here: ... M_Emulator


Re: Introduction

Posted: Mon May 15, 2023 5:05 am
by MicroCoreLabs
Here are a few pictures of the EPROM Emulator in action in an IBM PCjr:



Re: Introduction

Posted: Mon May 15, 2023 11:41 pm
by LeoBinkowski
This is a great project. I bought one of these because I was intending on some ROM exploration. I haven't yet made it to that task, because I need to get a full repair job on all of them before I trust new hardware in them.