New MMC1 and MMC3 boards

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poorstudenthobbyist
Posts: 231
Joined: Fri Jun 24, 2016 4:20 pm

New MMC1 and MMC3 boards

Post by poorstudenthobbyist » Sun Feb 07, 2021 8:03 pm

I made my own MMC1 and MMC3 boards that use the AX5904 and AX5202 clone mappers.
Support for most SxROM and TxROM board types (no TQROM, TR1ROM, TVROM, SOROM, SXROM, or SZROM right now).
New versions will support more coin cell and battery holder footprints, but any other critiques are completely welcome. Roast away.

MMC1 front
mmc1_1.jpg
MMC1 back
mmc1_2.jpg
MMC3 front
mmc3_7.jpg
MMC3 back
mmc3_6.jpg
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

You can also follow me on Twitter for infrequent updates and bad jokes!

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Ben Boldt
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Location: Minnesota, USA

Re: New MMC1 and MMC3 boards

Post by Ben Boldt » Mon Feb 08, 2021 11:24 am

It looks great. I am not sure if I have seen a board with the expansion pins grounded before, but probably not a bad idea. I was wondering, why not make 1 PCB that you can stuff with MMC1 or MMC3? Is there a reason that wouldn't work?

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poorstudenthobbyist
Posts: 231
Joined: Fri Jun 24, 2016 4:20 pm

Re: New MMC1 and MMC3 boards

Post by poorstudenthobbyist » Mon Feb 08, 2021 11:44 am

Oh, the EXP pins aren't grounded, they float. It just looks like they connect to the GND plane because of the way I set up the copper plane restrict areas, it looks like they connect but there is daylight between them.

I have a combo MMC1/MMC3 board in the works but it has a bunch more solder pads on the back to switch between modes (TxROM and SxROM). The idea being you can put both MMC1 and MMC3 in at the same time and be able to switch between them without causing conflicts, and then use sockets so you can make an all-in-one test board. Still toying with it.

Thanks :)
Check out my website for NES, SNES, and Genesis tutorials here. And visit my store for some custom tools and boards for making games here.

You can also follow me on Twitter for infrequent updates and bad jokes!

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