nesdev.org

Hello, first time poster here.

First some background info: (skip if you want)
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Some time after the new year I got a sudden urge to play older games on real hardware. Emulation didn't feel right, even with real USB controllers. I went down to the basement and located my NES and SNES, still in working condition, though the plastic had yellowed quite a bit on the both of them unfortunately. What's freaky is I got the NES front-loader in 1990 and have never changed the connector, it's been packed up in the basement for at least 5 years and every game I've tried has booted up on the first try.
I also didn't like the way the games looked on modern LCD screens, so I managed to find me a Sony Trinitron 36" WEGA for cheap, retro games look absolutely stunning on this thing! Such a beast to get into the house though, probably around 100 kilos, thank god my apartment is on the first floor.

I then stumbled upon some information about writing roms to cartridges. So I ordered 2x EEPROMs (AT28C256), a GQ-4X programmer, Hakko 808 desoldering gun (this thing is awesome) and some other stuff to get going. I plan to print out custom labels and even boxes in the future to store the games on my gaming shelf.

So the first project was to put a certain nes homebrew on cartridge. I found this document a great reference to know which game I could "sacrifice" and settled for Balloon Fight.

Desoldered the original mask roms for PRG and CHR, programmed my own EEPROMs and soldered four wires and tested it out. And it worked! Plays great and I've played it for hours a day already..
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Now, for my second project and the questions that I have. I was browsing around on romhacking.net and found a really fun hack of Super Mario Bros called Super Mario Unlimited. The only problem is, the original SMB is NROM at 32k PRG / 8k CHR and after patching it's a 128 KByte PRG (8 banks x 16 KB). I can't put this back on an NROM pcb, am I right? So basically I just need to know which type of cart I need to use to put the rom back on.

I also just found out about the INL-ROM pcb that can be ordered and I'd be very interested in using that if possible. Can I use the INL-ROM for this purpose, and again which mapper board should I order in that case? I don't care for EPROMs since I don't want to have to use UV eraser. So using AT29C010 EEPROMs with my GQ-4X would be more convenient.

So, is it possible to use AT29C010 EEPROMs with INL-ROM? Which mapper type INL board would I need? The original smb rom uses nrom but the prg-rom is now 128k instead of 32k so I don't think I'll be able to use nrom? Using the EEPROM described, how would I wire it up? Or can I just solder it in without the need of rewiring the pins?

Sorry if I'm asking dumb questions, I'm quite new to this whole thing.

Thank you in advance.

Burbruee wrote:Emulation didn't feel right, even with real USB controllers.

By "real USB controllers", do you mean some Gravis or non-name Chinese brand, or do you mean an authentic Nintendo brand controller through an adapter? Part of what makes it not feel right might be input or audio latency.

after patching it's a 128 KByte PRG (8 banks x 16 KB). I can't put this back on an NROM pcb, am I right?

It won't work on NROM.* What mapper does that hack use? An emulator's log file should tell you that, or you can interpret the first 16 bytes with a hex editor. More than likely, it's either UNROM (mapper 2) or MMC1 (mapper 1).


* Some experts build mapper developer boards out of NROM board with the ROM removed and ribbon cables to a breadboard, but I'm not talking about that.

The aforementioned ROM hack is MMC1, and it seems to run correctly without RAM; i.e. Nestopia calls it SFROM.

Hi. Sounds like you jumped in with both feet!
Well, you could re chip a SFROM board with slight re wiring for the PRG rom. You should be ok with the CHR rom if the hack uses 32K. If it uses a 64K image you will need to do some extra work, because the SFROM boards have a 28 pin footprint for the CHR ROM. Here is a list of carts that are SFROMs from the BootGod DB (my goto for cart info):
http://bootgod.dyndns.org:7777/search.p ... 9+20+41+53
INL may be able to help you out with one of his SLROM boards (it's very similar to SFROM but with a larger CHR Rom). I'm not familiar with what/any differences between the SF and SLROM in how they are controlled with the MMC1 and the wiki didn't go into detail, so there is still research to be done. But if you go the flash route, you will be happy with the Kazzo/Retro board setup; so much easier than the 'pulling the chips, erasing and re burning' routine.
Here is a guide for a SNROM Dev cart conversion that I have used, it may help you with rewiring the PRG eprom.
http://www.54.org/sage/condev/ff2cartproject/
Of course you can skip all the stuff about patching the rom I'm guessing that the changes for the PRG rom wiring is the same for both boards, but I could be totally wrong; never messed with any other mappers then SN and SXROMs.
Good luck and let us know how you fair.
EDIT: Oh here is the wiki pg for SxROM
http://wiki.nesdev.com/w/index.php/SxROM
May help you sort things out.

Ah, silly me. Didn't notice that the mapper changed after patching. Indeed it is now mapper 1. (MMC1)
I'll investigate further tonight when I get home and report progress. If I remember right from the top of my head then it was a 32k CHR so SFROM board as suggested by yogi might work out. Thanks.

Hi there I also would like to make a super mario unlimited. Please let us know how things go. Thanks and good luck