Reprogramming Cartridges

[Dylan]

I have a few questions about reprogramming cartridges. I don't intend to make actual reproduction carts, but I would like to program English patched ROMs onto some of my SFC RPGs. So without further ado:

Is all I need an original copy of the game? I assume that there wouldn't be a better cartridge than the original, considering that it contains the exact same components. This also justifies my personal morals in making the cart.

What's a good programmer to use? And does one programmer fit all? What I mean by this is that I would like to reprogram more than just SFC carts in the future, and it would be great if I only needed to buy one programmer.

What's the difference between ROM types? I've heard that EEPROMs can go bad, but I'm not sure what the consequences of that are. Are programmers able to use different types of ROMs? If that's the case, are there better alternatives to EEPROMs?

My knowledge of this subject is limited, so any help is greatly appreciated.

[Ziggy]

Is all I need an original copy of the game? I assume that there wouldn't be a better cartridge than the original, considering that it contains the exact same components. This also justifies my personal morals in making the cart.

Good man. Using the original cartridge is definitely the best way to go, since you don't have to sacrifice another game to make the one you want.

What's a good programmer to use? And does one programmer fit all? What I mean by this is that I would like to reprogram more than just SFC carts in the future, and it would be great if I only needed to buy one programmer.

I would go with a Willem programmer, they're about $40-50 depending where you get them. If you don't mind spending a little more, MCUmall makes a really nice USB model. With these programmers, you can program all the common memory that you would use inside game carts.

What's the difference between ROM types? I've heard that EEPROMs can go bad, but I'm not sure what the consequences of that are. Are programmers able to use different types of ROMs? If that's the case, are there better alternatives to EEPROMs?

I like to compare mask ROMs (the chip that contains the game data inside a game cart) to hard pressed DVD/CDs and (E)EPROMs to DVD/CD-Rs. It is said that mask ROMs are permanent and will never suffer bit rot. EPROMs or EEPROMs can suffer from bit rot. However, I wouldn't worry much about it. Most manufactures guarantee 10 years, but they usually last a lot longer than that (in the right conditions). Stick with a good name manufacture (ST, AMD, etc) and you should be fine. But even in the event of bit rot, you can always reprogram the chips since you want to get a programmer for yourself.

By the way, EPROM = Erasable Programmable Read Only Memory and EEPROM = Electrically Erasable ROM. The difference is quite simple. EPROMs are erased by exposing the window to UV light (in an EPROM eraser). You could also get OTP (One Time Programmable) EPROMs that don't have a window. With these, you can write them once and that's it. The benefits of this is they're cheaper (compared when buying new, not used) and you don't have to cover the window (which is good practice). With EEPROMs, you can erase them using your programmer which is a lot more convenient. All of the above mentioned types of memory can suffer from bit rot).

If you're gonna do a lot of SFC games, I'm assuming they're the popular titles that every one wants: Seiken Densetsu 2, Terranigma, other RPGs, etc. The thing with the RPG games is that they're usually 32Mb games (rarely you'll get a one that's only 16 or 24Mb). So a 32Mb game would require you to use 4 EPROMs. The alternative to this is using a newer flash memory in the TSOP package, but that requires you to use an adapter board. This isn't very practical if you're only gonna make a handful of games, but much more convenient if you're gonna be making a lot. It ends up costing the same or more. You also would have to buy adapters for your programmer.

Common SFC that you would do that are not RPGs will be a lot easier because they're usually smaller games, though there's not too many of these. Only one I can think of off the top of my head would be Little Magic, its only a 4Mb game. Shin Megami Tensei is only 16Mb.

[Dylan]

Thanks for the reply! A lot of good information there. I do have to replace the chip for the ROM? If that's the case I better start some small soldering projects, because I haven't got any experience at the moment.

Do you have any good resources you could suggest for these types of projects?

[3GenGames]

I'd first maybe try to go super simple....get a Atari cart and try reprogram it. Alot of systems, like NES, use MASK ROM's so the pins are in different orders a little and won't work by just plugging a EPROM in there.

[Dylan]

I'd first maybe try to go super simple....get a Atari cart and try reprogram it. Alot of systems, like NES, use MASK ROM's so the pins are in different orders a little and won't work by just plugging a EPROM in there.

I see, so different games will have different layouts on the PCB? Is there a good way to get comfortable with this? Maybe I should just try a basic course in electronics first.

[3GenGames]

Well....since I only know NES stuff...games that use 16K and 32K PRG ROM'S and 8K CHR-ROM'S (NROM boards) can just have another ROM popped in there with another game's program and characters that uses the same board and play, but for games that uses bigger ROM's, they mostly are reqired. Just compare the chips and match up the pins and it should work, but yes, you need to know how electronics work to do this and not be scared/do it right.