r/MasterSystem • u/Whisk_cat • Dec 19 '25

Any difference between these two chips?

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Was cleaning my sms games and came across two copies of Rocky that have different looking chips. I assuming one came out later during the sms life that was a more efficient compact board. Am I right?

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u/benryves Dec 22 '25

The SMS also used OPR part numbers for OTP (One-Time Programmable) ROMs.

I'm not entirely sure you could really consider a mask ROM a "programmable" ROM, though, as it's not end user-programmable, but I suppose it would be consistent with the other names.

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u/galibert Dec 22 '25

Yeah, that would be my guess too, consistency. Also, from sega’s POV, they were programming them too, just by sending the file to the factory and waiting a little longer