I tried a MCU only approach on SMS for banking a parallel Flash, and the 16MHz ATmega is not gonna make it unless it adds a waitstate for every Z80 cycle. 20MHz chip would have no problems however.... but no time whatsoever for any other task than listening bus and receiving and putting bank values...
NES has ~half the bus speed though, so that will tremendously help.
INL-ROM custom MMC3 hybrid mapper design
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infiniteneslives
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Re: INL-ROM custom MMC3 hybrid mapper design
Even with the NES at half the bus speed PRG bank switching isn't even half the game. CHR is where the complex bankswitching is really going on which is ~3 times as fast, that's a real deal breaker for mcu bankswitching especially if you're trying to do both PRG & CHR. That's why I like this approach where the mcu has nothing to do with bankswitching. Bankswitching really only belongs in the hands of a CPLD.
If you're gonna play the Game Boy, you gotta learn to play it right. -Kenny Rogers
Re: INL-ROM custom MMC3 hybrid mapper design
This project looks great!! Me personally I've been looking for a MMC3 tkrom 256kchr / 512kprg / 8kwram cart I could buy both for testing on the actual NES and to make carts of my homebrew once it's done.
Powerpak seems to have some unique issues.
Powerpak seems to have some unique issues.