New MMC1 and MMC3 boards

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

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poorstudenthobbyist
Posts: 252
Joined: Fri Jun 24, 2016 4:20 pm

New MMC1 and MMC3 boards

Post by poorstudenthobbyist »

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
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Ben Boldt
Posts: 1149
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: New MMC1 and MMC3 boards

Post by Ben Boldt »

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?
poorstudenthobbyist
Posts: 252
Joined: Fri Jun 24, 2016 4:20 pm

Re: New MMC1 and MMC3 boards

Post by poorstudenthobbyist »

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 :)
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