Menadue's Raspberry Pi Pico-Powered ROM Dumper Is a Cheap Tool for ROM Preservation via Mail
With an interesting piece of vintage equipment too far away fro a visit, Menadue's borderline-disposable ROM reader gets the goods by post.
Pseudonymous maker "Menadue" needed a way to receive ROM dumps of a device located in an entirely different country and owned by someone with no access to the necessary equipment — so set about building a ROM reader cheap enough to be considered a single-use device.
"What do you do if you want to dump the ROM in some equipment that is owned by someone else, who is happy to have their ROMs dumped, but who live in another country? They are probably not too happy sending things through the postal system as loss and damage is common these days," Menadue explains. "To solve this problem (and also allow me to dump some of my own ROMs) I made a little gadget that can dump a ROM that is plugged into it."
Menadue's tool is built around a Raspberry Pi Pico, the $4 microcontroller board powered by the RP2040 chip. A carrier board includes a socket aimed at 24-pin programmable read-only memory (PROM), erasable PROM (EPROM), and electrically erasable PROM (EEPROM) chips, plus a few passives — but little else, with the small bill of material making the device as cheap as possible so that if it is damaged or lost in the post another can be sent out easily enough.
Making the device cheap is one thing, but it also had to be easy-to-use — and it most certainly is: "Plug in the ROM, power up the gadget and wait for an LED to flash and you are done," Menadue explains of the device's operation. "The gadget can be posted to whoever has the ROM, they plug the ROM in and turn the unit on. After the light flashes, the unit is sent back to the person who needs the ROM dump."
There's another reason the tool should be considered effectively disposable, though: it works outside the Raspberry Pi Pico's official specifications, pushing 5V into pins designed for 3.3V logic. "There are no level shifters on this circuit," Menadue explains. "The ROM is indeed a 5V device and is wired to the USB 5V supply.
"A while ago I read, somewhere on the internet, that the Pico GPIOs [General Purpose Input/Output pins] are actually, probably, 5V tolerant. This seemed like a good project to test that out on. I've used this to dump some ROMs I wanted images for and it has worked well."
More details are available on Menadue's blog, while the hardware design files and RP2040 firmware are available on GitHub under an unspecified open-source license.