SFC Repro cart noob questions

[midirams]

alright, im going to PM the creater of the translation to find out, ill post whatever he says here in case anyone else in interested

[midirams]

Voultar's S.Stacker can actually work in this arrangment, instead of stacking them you just install one on each mask ROM. That info is in his installation PDF.

I thought the s.stacker only works with 36pin mask roms. How would I apply it to the 32pin one?

[Ziggy587]

alright, im going to PM the creater of the translation to find out, ill post whatever he says here in case anyone else in interested

In regards to the first 16 Mb matching up? You can actually pretty easily figure that out yourself, and this would be worth learning to do for future repro making. Just split the first 16 Mb off of the vanilla ROM as well as the translated ROM (you'll have to know how to do this anyway) and then compare those two files to each other. Probably the easiest way to compare two files would be in a hex editor, at least that's how I normally do it.

I thought the s.stacker only works with 36pin mask roms. How would I apply it to the 32pin one?

The same way. The S.Stacker works with a 36-pin socket, the mask ROM is inconsequential. When you clip the /OE pin on the mask ROM and tie it high, you essentially take it out of the equation. You could actually remove the mask ROM entirely and still use the S.Stacker, it makes no difference. It's the socket that's the important part. So if you look at your Fire Emblem PCB, you can see that the 32-pin mask ROM is installed in a 36-pin socket. There are four unused holes. So when you install the S.Stacker in that position, you would solder it to the mask ROM's 32 pins as well as those 4 unused holes. 32 + 4 = 36. The SNES 36-pin mask ROM pinout is actually identical to the 32-pin version, just with four more pins.

[midirams]

I'll admit, I think I've bitten off a bit more than I can chew, at least for now . I'm gonna look into more about how the snes components actually function in order to better understand what that diagram even means. But again, super grateful people on here are willing to point me in the right direction.

[Ziggy587]

This page gives a very good high level explanation of the various parts on a SNES cart: https://mousebitelabs.com/2019/05/18/cu ... planation/

edit: These pages as well...

https://mousebitelabs.com/2017/09/14/ho ... cartridge/

https://mousebitelabs.com/2020/07/08/mu ... ard-guide/

[SB_Electronics]

There’s definitely a lot to learn with SNES repros due to the shear range of variance. Not to mention that Nintendo carts have always used proprietary mask Roms with custom pinouts rather than standard pinouts, otherwise reproductions would be a lot easier.

I like to buy Japanese carts and translate them because I get a nice cart with all the parts I need including labels. Also it’s a hell of a lot cheaper.

First identify what game you want to translate. Then identify what mask Roms it already uses. This is where using an emulator and/ or SNES rom tools will help.

The diagram posted above shows the difference between the 8mbit and 16mbit mask Roms compared to a generic 8mbit EPROM. The pinout is the same for SNES mask Roms except the top 4 pins. As stated above by Ziggy, a 32 pin rom can be put on a 36 pin pcb and quite often was the case as some pcb were shared between different cart productions (check https://snescentral.com for more info).

For example - a 1Megabyte rom is 8mbit (8 bits to the byte). This will fit on a 27C801 EPROM (though the pinout will vary slightly). This is the easiest one to swap out because it is a 32pin DIP package same as the mask rom with minor rewiring. A lot of SNES games fit in this category.

A 2 megabyte rom is 16mbit. Unfortunately there is no 16mbit EPROM that fits on a 36 pin DIP package so you have to use a TSOP adapter. Sometimes the translation or mod will increase the size of your Rom.

I’ve got a JP Final Fantasy VI that uses 3 x 23C801 mask rom so I will need to replace all the Roms with 3 x 27C801 EPROMs (or just the ones that contain the language).

Star Ocean on the other hand is a 36mbit (and 16mbit) on a 44 pin SOP package. The only pin compatible EPROM is super rare/ non-existent. People have used a 3.3V EPROM but this is not electrically sound practice. Again an adapter would be needed. The same is required for SA-1 conversions.