NES Mapper 99, in hardware form?

[declan]

Hi all
Regarding Mapper99. The chip itself doesn't even exist right? Its just a Mapper code developed for using Unisystem VS games with NES emulators.

So, my question is, is it possible to hack up Nestopia (or an other emulator that supports MMC99) and extract the MMC99 code and place the code on.... i don't know, some kind of programmable locic chip, and use it on real NES hardware?

I ask because i would like to make a SMBVS cart.
I could also mod the NES console to accept raw VS files; using Raphaël Assénat's method: Modding a NES to run Unisystem VS arcade games.

The problem with that is, its a very complex procedure and there's no garentee it will work (with so many wires and switchs, i'm bound to make atleast one mistake).

It would be much easier if i could use MMC99 on real hardware.

ALSO: i wouldn't need to patch the colour palette either (Unisystem VS uses a different PPU and different colour palette) if i could use this mapper.

Any of your thoughts are appreciated

[whicker]

declan,

find something better than this specific project to spend your time on.

[declan]

Its like that huh?
Not to worry, it was just a thought.
I guess i have a bad habit of thinking up dumb project ideas....
Cheers man.

[whicker]

don't be embarassed.

it's just that you need to realize how powerful and useful that PC sitting next to you is in comparison.

I've got strange (but ultimately useless) ideas like putting a Parallax Propeller chip into a SNES cart, and making the ultimate SD-card multicart. But then issues like boosting 3.3V to 5V and back creep in.

Go ahead and laugh at my insanity.

[declan]

*laughs at whicker's insanity*
I see your point now.
Well i'm glad we had this little chat, before i lost any sleep over it.

From now on, my faith lies with emulators.
sort of

[Snark]

Well personally, I don't like the idea of emulators making up "hardware" that never existed in real life. And for those virtual "hardware" that were first made in emulators I like having proof of concept.

So yeah, it might be neat if someone could pull off a "pseudo mapper" to real life hardware. Nestopia is an extremely accurate emulator so I would guess, or suppose at least, that it would not support something if it wasn't possible in theory. So what you're asking is likely possible, now as to how you could make that I wouldn't even know where to begin.

[declan]

now as to how you could make that I wouldn't even know where to begin.

Probly need to reverse engineer the algorithum of one of these "pseudo mappers". Then design a program that could get a microcontroller of some description to imitate to workings of the mapper code.
That said, i'm still going to go with what whicker said, and not waste my time on such and experiment

[PHoNyMiKe]

or you could just http://www.retrousb.com/index.php?productID=133


p.s. mappers aren't some god like configuration device meant to foil peoples' brains like the nes lockout chip. mappers simply detect a pattern and change to a different memory area. the nes has like 128KB memory space for rom. so if you want more space, you can put in 256KB rom cart, but you need a mapper, otherwise the nes can't see past 128KB. the nes can read the first 128KB, then you send the cart a command to bankswitch by writing to the rom. the rom is read only so nothing happens but the mapper got its command so it switches to the second half of the 256KB chip and the processor can read more shit to send to the vram so you can see pretty graphics. mappers just turn the page in a book.

[Gil_Hamilton]

or you could just http://www.retrousb.com/index.php?productID=133


p.s. mappers aren't some god like configuration device meant to foil peoples' brains like the nes lockout chip. mappers simply detect a pattern and change to a different memory area. the nes has like 128KB memory space for rom. so if you want more space, you can put in 256KB rom cart, but you need a mapper, otherwise the nes can't see past 128KB. the nes can read the first 128KB, then you send the cart a command to bankswitch by writing to the rom. the rom is read only so nothing happens but the mapper got its command so it switches to the second half of the 256KB chip and the processor can read more shit to send to the vram so you can see pretty graphics. mappers just turn the page in a book.

You can also have the mapper set up to switch banks on reads to specific ROM addresses.
Which do nothing because the mapper intercepts the reads and interprets them as commands, so they never get data passed back.

[declan]

the nes has like 128KB memory space for rom

The 6502's (or 2A03 in the nes) address bus only 16 bits wide.... that's a mere 65536 bytes (or 64KB) of data.

that's a mere 65536 bytes

I wonder if the "65" in 6502 came from the fact that it has 16-bit address bus??????

[grinvader]

I wonder if the "65" in 6502 came from the fact that it has 16-bit address bus??????

I wonder if the "65" in 65816 comes from the fact that it can address 16 megabytes??????????????????

[declan]

Ok.
I addmit, it was a dumb comment