hi all, i was wondering if anyone has made their own flash carts or modified a normal cart to be a flash cart?
i am trying and failing so i want to ask some questions
thanks!
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Minneapolis
Not for GB, but for NES. I could give you some help though, since the concepts are similar.
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Sweeeeeeden
i don't have any actual practical experience, but perhaps I can help you anyway. You know where I am.
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Milwaukee, WI
GBDev has a lot of useful stuff on that. Otherwise you could build the design on reiner zeiglers website.
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Adelaide, Australia
I too have tried and failed, based on Reiner Ziegler's guide to replace the ROM chip in a Zelda cart. I'm not very good at working with wrap wire. 
I might give it anther go one day, though.
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well i need to know what exactly the two pins on the MBC5 board do (RA20 and RA21) because my cart doesn't have the MBC5 chip but it did have the LH538 ROM chip.
i assumed that if people have swapped out the rom chip from a LH538 to a AM29F016B then the wiring must be the same and the cart should be able to support the new flash memory, but i don't know where to run the last two wires.
at the moment when i boot up i am getting a scrambled nintendo logo. the chip is already flashed with a working rom, the cart contacts are clean etc. i get the same pattern in all the gameboys so hopefully its just the last two wires that make it all ok. if not i have screwed up somewhere else....
thanks guys
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Adelaide, Australia
Well, in Ziegler's guide, RA20 and RA21 connect to A20 and A21, respectively. So at a guess I'd say these are involved in bank switching. Without MBC5 you can therefore only access the first 1024 kb of the flash, so maybe try a 1024 kb rom?? I take it you have a different MBC in there instead?
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freezedream wrote:
Well, in Ziegler's guide, RA20 and RA21 connect to A20 and A21, respectively. So at a guess I'd say these are involved in bank switching. Without MBC5 you can therefore only access the first 1024 kb of the flash, so maybe try a 1024 kb rom?? I take it you have a different MBC in there instead?
yea the MBC is a custom nintendo chip so there is no documentation on it.
the rom on there is a 1024 rom exactly
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Melbourne, Australia
Did you ground the unused address pins on your rom chip?
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TmTgr wrote:
Did you ground the unused address pins on your rom chip?
nope? do you think that could cause complete failure?
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Sweeeeeeden
Just so we don't exclude any possibilities... What is the speed rating of the flash chip? The speed rating is the last number in the part number, after a dash. It's typically something like -75, -90 or -120 and tells you how many nanoseconds the chip will take to deliver the requested data. Lower is better. -120 should work, -90 should definitely work, but anything above -120 might not. I find it hard to believe that such a big chip would be too slow, but you never know.
Can you tell me something about the scrambled logo?
Does it look the same every time? If no, then something is seriously wrong. ( 
)
Does it have any resemblance of the Ninty logo? If yes you've probably swapped or otherwise screwed up the data lines.
If neither of those, (same dirt every time) you're reading data from somewhere else in the ROM.
If the flash chip is actually programmed correctly, then there's something wrong with the address lines.
Any unused address pins should be grounded, otherwise they might fluctuate and this can cause a complete failure. However, since your cart doesn't use MBC5, I'm assuming it's using MBC3 or maybe MBC1. (But not MBC2, as MBC2 couldn't even handle the 8 MBit LH538...) Both MBC1 and MBC3 have a max size of 16 MBits, so you should be able to get the full size. You should be able to connect at least A19 by connecting it to A19 of the ROM. If there's only 1 unconnected pin left on the MBC, that's where A20 should go. Or you could ground A20 and live with having only 8 MBits for now.
Oh and if you haven't seen these:
http://www.ziegler.desaign.de/32mbit.htm
and
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nitro2k01 wrote:
Just so we don't exclude any possibilities... What is the speed rating of the flash chip? The speed rating is the last number in the part number, after a dash. It's typically something like -75, -90 or -120 and tells you how many nanoseconds the chip will take to deliver the requested data. Lower is better. -120 should work, -90 should definitely work, but anything above -120 might not. I find it hard to believe that such a big chip would be too slow, but you never know.
Can you tell me something about the scrambled logo?
Does it look the same every time? If no, then something is seriously wrong. (
Does it have any resemblance of the Ninty logo? If yes you've probably swapped or otherwise screwed up the data lines.
If neither of those, (same dirt every time) you're reading data from somewhere else in the ROM.If the flash chip is actually programmed correctly, then there's something wrong with the address lines.
Any unused address pins should be grounded, otherwise they might fluctuate and this can cause a complete failure. However, since your cart doesn't use MBC5, I'm assuming it's using MBC3 or maybe MBC1. (But not MBC2, as MBC2 couldn't even handle the 8 MBit LH538...) Both MBC1 and MBC3 have a max size of 16 MBits, so you should be able to get the full size. You should be able to connect at least A19 by connecting it to A19 of the ROM. If there's only 1 unconnected pin left on the MBC, that's where A20 should go. Or you could ground A20 and live with having only 8 MBits for now.
Oh and if you haven't seen these:
http://www.ziegler.desaign.de/32mbit.htm
and
ok the flash chip is a: AM29F016B-90SC so that should be all good.
the scrambled logo is a black block (as if there is no cart) but with some white dots in it. the white dots are in rows with about 3 black dots between. so kinda white black black white black black white. then again but lower down. i will try and take a photo.
yes its the same scrambled nintendo logo every time on every gameboy. so hopefully thats a good sign lol
instead of an MBC5 it has a MAC-GBD nintendo chip. the only other chip is the SRAM
the chip is from a bleep bloop cart, i programmed the cart and all was well, the cart worked fine then i carefully removed the chip and transplanted it. i am pretty sure all the wires are ok, i double checked them as i was doing them, and i checked for any shorts.
i don't have a programmer so i can't try reflashing the chip in its new home...
i will have a go at grounding the unused pins as well.
does that mean that this chip should work even without the last two pins to the MBC? if so i can double over my connections and check them all
i followed that pin out for a while :http://www.ziegler.desaign.de/32mbit.htm got about half way before realising it was for a 40 pin chip and not the 44pin that i was installing so i started again and followed this one:
http://www.ziegler.desaign.de/download/MBC5_Cart.pdf <---PDF file
is it possible that running this if it was wired incorrectly could have damaged the rom stored on it? and so would need reflashing?
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ok i grounded my address lines but no different, i am going to go for the horrible task of checking every wire, unless anyone has any other ideas?