Breadboard-less ROM dumping
So you want to dump a ROM, but don’t have a breadboard? You can use a Teensy, some female-female jumpers and if you have one, a ZIF socket. I cut the power and ground wires and soldered three additional leads to each one to provide hard-wired values for for Vpp and !PGM signals at +5V, and the !CS and !OE signals at ground potential. To make wiring easier, my code in prom.c maps the address lines sequentially down the left side of the Teensy, and the data lines sequentially down the right side. Using every pin on the teensy provides 14 bits of address line and 8 bits of data, allowing up to 16 KB PROMs to be dumped.
My goal was to dump the MBM2764-30 PROMs from an Oberheim DX that was in the backroom at NYC Resistor before the UV PROMs went bad. The DX1.4a and DX1.4b PROMs were not responding, but the musical instrument ones seem to be intact. Now to figure out a way to play the samples…
[…] # Breadboard-less ROM dumping. Recuperando información de viejas memorias ROM. Vía “NYC Resistor”. […]
[…] Hudson followed up last Sunday with a post showing how to snag a ROM’s data using a Teensy development board. Cool stuff! Share this: Pin ItLike this:LikeBe the first to like […]
[…] descobriram que estava funcional, resolveram tirar as ROM para dumpar (veja a motivação em posts anteriores deles) e disassemblar o conteúdo. Qual foi a surpresa deles em achar trechos de código que não […]