Hi everyone. I have recently been messing around with editing a megaman rom I have. Well I have it looking ok and wanted to put it on a real NES cart. I am aware of the diffrent mappers and such and I have picked out a cart that is of the same type as the Megaman Cart. The one I chose to sacrafice was Dragon Warrior. Anyway on the PCB for Dragon Warrior there are 5 chips total. 3 large and 2 small. My hope is to desolder the chip that contains the game data (or rom) and install a socket. Then I will buy a flashrom and burn my Megaman rom to it and install it in the socket. The only thing I cant figure out right off hand is which chip to pull and socket. I have a really good idea of which it is but I want to make sure before I have to tear up another cart. So can anyone tell me which to pull. 1 of the large chips is the PRG another is the CHR and the last large chip just says "SHARP" on it with some numbers, this is the one im thinking of. Any help is appricated. If this wont work and is stupid as hell to try then please let me know, thanks!:thumbsup:
PRG is program ROM. CHR is character ROM. The SHARP chip is probably backup RAM of some kind. When you say "cart that is of the same time" you do mean type, yes? As in the same mapper, not just released the same year? Also, do you have an EEPROM programmer yet? They can be quite expensive...
Yes this Dragon Warrior is the same Mapper as Megaman. Its the first mapper that was released I think. Anyway I know someone who has a EEPROM programmer but I had hoped to make one myself. So do you know what chip I would have to socket and copy the new data to? I was under the impression that all game data was stored on a single chip that I could pull then just dump a rom image to and put it in and I would be fine?
i think you will have to go back and read up some more before attempting this. first, you cant just pick any cart. you already know that you need one with the same mapper, thats good. however, theres more to it. basically, the data storage for graphics(chr) and game program(prg) is seperate. games have a prg rom where the program is stored. there can be additional ram on this bus, either for backup saves or extended work ram. the chr bus usually has either ram or a rom. if it has chr rom, you will have to split your rom file and program two eproms, one for the chr and one for the prg bus. adding chr ram to a cart with chr rom isnt a good idea, because most retail games just have the pins on the cart edge connector they need. that means chr rom carts are missing the chr write enable, for example. also, eproms dont neccessarily drop right into mask roms slots without rewiring due to different pinouts, depends on their type and size. some do, some dont. because youre doing a megaman hack, i'd highly reccomend getting the original cart of the game youre hacking and modifying that. this seems to be your first self-built cart and although you might have to shell out some 5 dollars more, it greatly simplifies the process. if you are sure that the cart you decided on is the exact same type as your megaman, thats fine as well. i dont like the nes that much, but built a final fantasy 3 cart with the english fan-translation a few years ago because i was curious. coincidentially, i used mega man 4 as a donor cart, because it has an mmc3 and chr ram, but had to add prg ram and the backup-battery powering circuit and thats something i'd definitively not recommend for starters.
..... ...... ... you.... just blew my mind..... Wow thats a lot of big words. Well the 2 carts have the same mapper I know that. The only thing I think may be diffrent is the fact that dragon warrior has a battary on it. I looked up some stuff on NES devwiki and it turns out there are some diffrences in the 2. Dargon Warrior is SAROM MegaMan is UNROM(the most common) SAROM: PRG: 128KB ROM CHR: 64KB ROM WRAM: 8KB + battery Mapper: Nintendo MMC1 UNROM: NES-UNROM is the most common board in the UxROM set. It supports up to 128KB of PRG ROM and 8KB of CHR RAM. Mirroring is selectable via solder pads on the cartridge PCB. UNROM: 128KB PRG ROM, 8KB CHR RAM, 74161+7432 8000-FFFF7 bit 0---- ----xxxx xPPPThe P bits select a 16KB PRG ROM page at $8000-$BFFF. The last PRG ROM page is fixed at $C000-$FFFF This board is susceptible to bus conflicts. That info is copied and pasted. Do think this has a snowballs chance in hell of happining??? lol, this way harder then it should be, the NES is what, 22 years old
The NESDev messageboards have a section just for this topic: http://nesdev.parodius.com/bbs/viewforum.php?f=9&sid=a2c432a063f7ba9adef31c85e1be8d9b And NESDev is a great place in general: http://nesdev.parodius.com/bbs/ Yes, the NES is old, but don't underestimate the complexity of something just because of its age. For general NES tech info, please check out the FAQ I made some time ago: http://www.disgruntleddesigner.com/chrisc/NESTechFAQ.html Especially question #32 which deals specifically with your question. At the end I note that "This is not a beginner's project." And it's true. And please note that EPROMs are not the same as EEPROMs. For ROM sizes larger than 32kbytes, I'm pretty sure that only EPROMs will do. As MegaMan is 128kbytes, I'm sure that you can't use EEPROMs. As for the mapper, MegaMan and Dragon Warrior are not compatible. You need to choose a game that uses UNROM, and has a RAM chip for CHR graphics. Dragon Warrior uses ROM, so it is unusable for your purposes. There are many games that use the same configuration (UNROM, 128k PRG, CHR-RAM, Vertical mirroring) as MegaMan, so use this list as a guide: http://gavin.panicus.org/doc/Bigass Mapper list.txt
