Relatively Universal ROM Programmer Is Relatively Universal and Only $9

Electronics YouTuber Anders Nielsen's latest video introduces the Relatively Universal ROM Programmer project. This Arduino shield lets you erase and program 27-series electrically-erasable programmable ROMs (EEPROMs), and serves as an alternative to much more expensive off-the-shelf programmers.

The Relatively Universal ROM Programmer comes as an Arduino Uno shield form factor, which means you need an external microcontroller to program the EEPROMs. The shield provides the two high-voltages required to erase and program the EEPROMs. EEPROMs in the 27-series lack a UV window typical of DIP-style EPROMs. Instead, they are electrically erasable.

One option to drive the shield is to use an Arduino Uno. Another is a past Nielsen project. The 65duino is a single-board computer based on the 6502 8-bit microprocessor that offers an Uno shield header layout.

This programmer is "Relatively Universal" because it relies on the JEDEC ROM footprints standard to 24-, 28-, and 32-pin DIP-style ROM chips in the 27-series. In this case, high voltage ranges from 5 to 27 volts. Nielsen's design uses BJT drivers to provide those voltages on the appropriate pins with a precision potentiometer (trim pot) to calibrate the voltage levels. While the "high-voltage" pins are software-controlled, you need to set physical jumpers based on the chip/package size for the EEPROM.

This solution is ideal for anyone who only needs to program DIP-style EEPROMs. Other, more expensive programmers can program a much more comprehensive range of devices. However, as a programmer specific to 27-series EEPROM devices it is a very affordable tool. There are several ways you can add one to your electronics toolbox.

You can buy a pre-soldered SMD kit for around $9 (without a microcontroller board). Alternatively, Nielsen provides all of the KiCad design files, PCB Gerbers, and assembly files necessary to order one from a manufacturer from the Relatively Universal ROM Programmer GitHub repository.