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Still use SRAM or move to eeprom ?

Posted: Sun Mar 27, 2016 10:12 am
by KanedaFr
Hi
for new game, does it still make sense to use SRAM ?
I mean, why not use (now) low cost eeprom and not sram + battery holder + battery ?

The only thing I saw is emu support, since eeprom support is per game.
because cost is no longer a problem, no ?

Re: Still use SRAM or move to eeprom ?

Posted: Sun Mar 27, 2016 10:50 am
by Sik
Fusion seems to look at the header to determine if the EEPROM is used since it's the only emulator that doesn't barf on Game Toshokan if you don't null out the EEPROM functions (it's probably looking at the fact that external memory starts and ends in the same address). Flashcart support is a much bigger issue since they usually only emulate SRAM instead.

Also the fact that EEPROM is harder to program so that probably discourages people from using it in favor of SRAM which is trivial to use (and you can even use its data directly from there).

Re: Still use SRAM or move to eeprom ?

Posted: Mon Mar 28, 2016 10:21 pm
by Mask of Destiny
As far as emulator support is concerned, it's easy to detect whether a game uses EEPROM (generally indicated in the header in the manner Sik mentions), but there's no reliable way to determine how it should be actually wired up and what capacity of EEPROM it has short of having a list of EEPROM games containing the relevant metadata. It would be nice if we had a ROM format that allowed for extra metadata describing things like EEPROM hardware and weird mappers so that new homebrew using that hardware would just work, but I have my doubts such a format could gain traction at this point.

If you're planning on doing a hardware release though, going with EEPROM seems like a slam dunk. Lowers your part count and there are far fewer traces to route for your save hardware (assuming a serial EEPROM anyway). It is indeed harder to program, but the additional programming burden is not extreme and it seems to me the unit cost advantages are worth it.

Re: Still use SRAM or move to eeprom ?

Posted: Tue Mar 29, 2016 12:45 am
by KanedaFr
Yes, I'm talking about new release, hardware side.

The blank PCB we can buy are w/ or w/o SRAM
nothing about (serial) eeprom
I do understand these PCB are mainly used for repro but, on our side, what would be the best bet ?
from capabilities and price side...

Need to compare SRAM / EEPROM (/ NVSRAM / FeRAM)
save capacity vs IC(s) price vs board price vs life time...

Re: Still use SRAM or move to eeprom ?

Posted: Tue Mar 29, 2016 12:59 am
by Sik
Mask of Destiny wrote:It would be nice if we had a ROM format that allowed for extra metadata describing things like EEPROM hardware and weird mappers so that new homebrew using that hardware would just work
Don't even dare >=|

Mind you though, there's still some space left in the ROM header that obviously Sega won't populate anymore =P May as well use that for extensions.