Game Gear Mask Rom Alternative

[Tormenter]

Does anyone know of a mask rom that will work on a game gear cartridge? There are a couple of translations I would love to play, but I hate flash carts, I enjoy building my own. Would prefer SOP type (not like the NES chips). Thanks

[lidnariq]

Looks like a standard 32SOP? See if the SST39SF0x0 chips are the right dimensions?

[Tormenter]

Looks like a standard 32SOP? See if the SST39SF0x0 chips are the right dimensions?

Thanks. Can't really find any info on that chip, no datasheet or nothing.

[lidnariq]

You're not going to be able to find anything from the part number, but I really bet it's a standard SOP-32 1Mi × 8 mask ROM. If you have a cart in hand, you should be able to use a ruler (calipers would be ideal, but even just mm or 1/16th of an inch will do) to see if it's the same as the SST39SF040 SOP32 spacing and width.

[Tormenter]

Okie thanks. I don't have any calipers, but been meaning to order some, so just did =P hehe

[ccovell]

I don't know much about GG games, but almost all SMS games use custom ROMs with an integrated mapper. I imagine that large GG games can only be the same, so if you use a standard EPROM in their place, you'll only be able to put games on up to 48k.

You can look for more info at http://www.smspower.org, but I'd say you're better off with a flashcart.

[lidnariq]

I was assuming the extra IC on the PCB seen here
http://www.digital-circuitry.com/GameGear_Carts.htm
was the banking IC
http://www.smspower.org/Development/MapperPinouts

although clearly several of the games did integrate one

[Tormenter]

I have made myself many SMS games, and never had an issue with any of them with a straight solder job.

[tepples]

What country are you all in? Perhaps the assembly lines making SMS games for North America, Europe, and South America didn't all use the same boards. I'm guessing Sega might have used external mapper ICs (315-5208, 315-5235 or 315-5365 per this article) in some countries but a custom mask ROM with integrated mapper in others, either as a custom die or as a multi-chip package. Or perhaps the integrated mappers came later.

[Tormenter]

US

[Tormenter]

You're not going to be able to find anything from the part number, but I really bet it's a standard SOP-32 1Mi × 8 mask ROM. If you have a cart in hand, you should be able to use a ruler (calipers would be ideal, but even just mm or 1/16th of an inch will do) to see if it's the same as the SST39SF040 SOP32 spacing and width.

20.35mm if I am using it correctly

[lidnariq]

Which would be 801 thou ... probably actually 800 thou ... pin spacing is probably 50 thou? That sounds standard to me.

Check the footprint / package width, too.


... wait a moment, Microchip isn't selling the SST39 series in SOP anymore? Awkward. The AT49F and AT28C series look like they were the right form factor, but they're also out of manufacture.