The Teensy 4.0 runs at more than 600Mhz, contains 1 MB of RAM, and is supported by the Arduino IDE development tools, so is an ideal and simple platform to emulate ROMS and EPROMS.
All the Teensy needs to do is sample the 16 address lines, retrieve the data from a 64 KB array, and then drive the data lines to support EPROMs sizes up to the 64KB 27C512.
Uploading a new ROM image takes seconds and is as simple as updating the data array then reprogramming the it using the Arduino’s IDE.
The small PCB contains three SMT buffers to convert voltages as the Teensy is not 5V tolerant. This board plugs into the EPROM socket and the Teensy plugs into this board.
The setup you see below is somewhat tall because, rather than soldering the Teensy directly to the board, I used sockets between the Teensy and the PCBA which added a lot of height. Without these sockets it would be much shorter.
The pictures show the board emulating the 32KB ROM in an IBM PCjr.