It's quite uncommon to find MMC1+MMC3 in one cartridge. Many multicarts that merge such games contain in fact patched version of MMC1 games that were hacked to MMC3. Modern cartridges prefer to use either CPLD or ASIC chips for that purpose.
The only cartridge with both chips that I knew so far was this one:
http://krzysiobal.com/carts/?action=view&id=528
until someone at famicomworld.com showed this. He did not respond to my help offer, so the best I could was to analyze his photos.
PALs definitely serve as PRG/CHR/CIRAM multiplexer between MMC1 and MMC3. All PALs share two inputs, so probably a mode selector (NROM/MMC1/MMC3/menu?)
There is also a huge reg (74273+74273+74161), not 100% sure where it is mapped, but probably clocked by MMC3-WRAM-/WE, so $6000-$7fff.
If someone spotted that before, a ROM dump of the menu would be useful.
NROM+MMC1+MMC3 discrete multicart
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- krzysiobal
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NROM+MMC1+MMC3 discrete multicart
My website: http://krzysiobal.com | My NES/FC flashcart: http://krzysiocart.com
Re: NROM+MMC1+MMC3 discrete multicart
oops, for the reason of nonsense, this post has been removed, sorry 4 that
Last edited by aquasnake on Sun Jan 28, 2024 6:55 am, edited 1 time in total.
- krzysiobal
- Posts: 1036
- Joined: Sun Jun 12, 2011 12:06 pm
- Location: Poland
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Re: NROM+MMC1+MMC3 discrete multicart
Owner of the cartridge said it contains Street Fighter 2, which uses MMC3 for CHR&IRQ, but has single 32kB PRG reg (mapped either to $4120 or $6000-$7fff.
That would explain the presence of 74157 and 74161 that latches D4 and D5, so this is
MMC1 + MMC3 + #189 + NROM?
That would explain the presence of 74157 and 74161 that latches D4 and D5, so this is
MMC1 + MMC3 + #189 + NROM?
My website: http://krzysiobal.com | My NES/FC flashcart: http://krzysiocart.com
Re: NROM+MMC1+MMC3 discrete multicart
oops, for the reason of nonsense, this post has been removed, sorry 4 that