SFC cartridges and low-profile EEPROM

This is an archive of a topic from NESdev BBS, taken in mid-October 2019 before a server upgrade.
View original topic
SFC cartridges and low-profile EEPROM
by on (#73820)
Just wondering: I've seen pictures of Super Famicom cartridges that have had the mask ROMs removed and replaced with a sort of converter board that allows a surface-mount EEPROM (TSOP package, I think?) to be plugged into a DIP socket. I have a couple SFC cartridges that I'd like to convert to use patched English ROMs (Final Fantasy V and Seiken Densetsu 3, respectively,) but I'd like to avoid the ugly "cut out a hole in the casing" approach with the "stacked DIP ROMs" method I've seen for SFC cartridge conversion. Are these TSOP->DIP adapters available commercially? Where could I obtain them? (Also, what do I do for cartridges of odd ROM size like FF5?)
Re: SFC cartridges and low-profile EEPROM
by on (#73828)
commodorejohn wrote:
Are these TSOP->DIP adapters available commercially?
yes,
Quote:
Where could I obtain them?
Ask google (your phrase "TSOP DIP adapter" works for me)
Quote:
(Also, what do I do for cartridges of odd ROM size like FF5?)
Uhhhhhhh. You could try some things, but I don't know what's right. Padding it with zeroes or $FFs is the first most trivial thing I'd try before I sweated trying anything more complex. Assuming you can reprogram the ICs without too much work.

by on (#73850)
Yeah, I guess that was a silly question. What I meant to ask was, are they available with an EEPROM already on them? I don't have any surface-mount equipment with which to attach one, so if they're not I'd have to find someone who could do it for me. If I did, what EEPROMs would be appropriate, as far as matching the pinout on SNES mask ROMs?

by on (#73870)
There aren't going to be adapter boards with flash already soldered on.
Now's the time to learn, I guess. It isn't even that hard-- put a smaller tip in your iron, put down a ton of solder flux, tape the chip down, go over it again with flux, clean your soldering iron tip, put a big droplet of solder on it, drag it across the pins, feed more solder as you're going across if it runs out.

It will "magically" work for the most part, but use solder braid to get rid of the three or so bridges between pins that do develop.

No pinouts match the mask chips perfectly, hence the need for an adapter board.

Anything that is 5 volts with enough address lines and an 8-bit data bus will work.

by on (#73890)
whicker wrote:
No pinouts match the mask chips perfectly, hence the need for an adapter board.


No offence/rudeness intended, but it would really help the guy if he was linked a proper, 100% accurate pinout mapping from mask ROM to EEPROM or Flash. This kind of response mimics what I've gotten from the nesdev community over the years when asking how to re-wire an MMC3 cart to permit EEPROMs (the response of which always is "it's not that hard, you just map pin X to pin Y based on the function of the pin", which though true is far from what all is required, pin-mapping-wise).

by on (#73891)
I can look at the pinouts and figure it out, probably, but it would help if someone had some more detailed information.

by on (#73903)
commodorejohn wrote:
I can look at the pinouts and figure it out, probably, but it would help if someone had some more detailed information.
I haven't really been studying the SNES as much as the NES — all I can point you at is http://wiki.superfamicom.org/snes/show/Ports+%26+Pinouts but I can't find any 5V 4MBx8 EEPROMs on digikey. SST sells some 512kx8 EEPROMs (SST39SF040) and you could stack 5 of them (augh) and Atmel sells (sold?) a 1Mx8 (AT49F8192A or AT49F008A) )that you could stack 3 deep.

(P.S. why the megazeux avatar?)

by on (#73906)
lidnariq wrote:
I haven't really been studying the SNES as much as the NES — all I can point you at is http://wiki.superfamicom.org/snes/show/Ports+%26+Pinouts but I can't find any 5V 4MBx8 EEPROMs on digikey. SST sells some 512kx8 EEPROMs (SST39SF040) and you could stack 5 of them (augh) and Atmel sells (sold?) a 1Mx8 (AT49F8192A or AT49F008A) )that you could stack 3 deep.

(P.S. why the megazeux avatar?)

Yeah, that's kind of the thing. I'd really like to avoid stacking EEPROMs, since that'd require me to cut a big ugly hole in the case, but I'm not sure how feasible that is. Guess I'll see...

(Also the avatar is because I was making a NES conversion of one of Kurushimi's joke games at one point, for no particular reason. Haven't actually done anything on it in quite a while though.)

by on (#73907)
commodorejohn wrote:
Yeah, that's kind of the thing. I'd really like to avoid stacking EEPROMs, since that'd require me to cut a big ugly hole in the case, but I'm not sure how feasible that is. Guess I'll see...
According to the SST datasheet, the TSOP EEPROM is 1mm thick, and using my calipers here, this random DIP 8kBx8 EEPROM is 4mm thick. It might work out...

by on (#73934)
commodorejohn:

Just pointing out this thread if you haven't already seen it...
There is actual PCB artwork, plus someone was willing to have these made at the time.

http://nesdev.com/bbs/viewtopic.php?t=6047