Codes on data east eprom stickers

Hello.
I wanted to ask about the EPROM stickers on Data East boards.
Is each game assigned a fixed two-letter code, which is found on the EPROM sticker? For example, "F K" for Midnight Resistance.
Is it possible that if a game was released on different revisions of the board, each release would have its own code?
Is it also possible that two or three EPROMs will have a code, say, XX, while the last EPROM remaining on that board will have a different code, like UU?

Maybe someone has knowledge and can tell me if there is any rule that Data East followed when selecting two-letter abbreviations for individual games, or maybe a list of all Data East games with the codes assigned to them?

/Mike

I've never seen any official info on how Data East assigned those codes.

If one EPROM has a different label, I'd just assume it was replaced at some point unless there's other evidence saying otherwise. Comparing a bunch of original sets is probably the only way to figure out if there's any pattern.

FastBall said:

I've never seen any official info on how Data East assigned those codes.

Click to expand...

I also never encountered any information about this. I was convinced that each game had a unique code that was used across all versions, but after examining several PCBs of the same game, I noticed that each had a different code.

misiequ said:

I wanted to ask about the EPROM stickers on Data East boards.
Is each game assigned a fixed two-letter code, which is found on the EPROM sticker? For example, "F K" for Midnight Resistance.
Is it possible that if a game was released on different revisions of the board, each release would have its own code?
Is it also possible that two or three EPROMs will have a code, say, XX, while the last EPROM remaining on that board will have a different code, like UU?

Click to expand...

In general a unique label mean unique code on those chips.

when a game gets released in multiple regions you may see different labels because some chips are the same code as the original region, and the chips with the different code are unique to the alternative region.

for instance if you look at the mame driver for midnight resistance you'll see that the USA region has all chips with code "FL", but then the european region has most chips with FL, but then only the Euro region specific chips with "FK"
https://github.com/mamedev/mame/blob/master/src/mame/dataeast/dec0.cpp

A lot of times these codes are arbitrary. F might just be the 15th game they released meaning it got the 15th letter of the alphabet as the prefix. other times they might reserve specific letters as the revision, or specific letters for specific regions.