Thanks man

. It would be great if I could use such a EPROM instead. This project was done by someone else years ago and I'm trying to replicate it.
Project entails upgrading a BGA304 CPU from 300Mhz one to an 600Mhz, which I hope to do by someone more experienced.
After this the old PROM needs to be removed and replaced with the new one which has the correct setup data for the new CPU. The PROM file is available as a .mcs file, which I assume can be used in an Atmel AT17LV256 EPROM?
It's been 15 years or so since I've programmed EPROMs in college (and then only for a bit), so I'll need to refresh my memory.
Project details:
http://www.sgidepot.co.uk/o2cpumod.htmlThis project is definitely out of my depth, but as I don't have anything better to do, I might as well try it ¯\_(ツ)_/¯.
EDIT: I checked farnell and mouser for similar chips. The Atmel AT17LV256 seems to be very similar to the Xilinx PROM with same pinout. So it's probably my best bet. I just have to find a programmer for it.