Hi, I just plugged on my N64 and it worked (3 years or more since I did not use it ). So I thinked I can reprogramm a original N64 cart? What I need? There is some tutorial, website whatever what talks about it? Thanks a lot. ;-)
IIRC N64 uses a serial rom and I believe the ones in the carts are mask roms, so you can't reprogram them. A v64jr is your best bet. smf
This is an interesting topic... you can't just swap the mask rom out with an eeprom (besides they don't make eeproms big enough anyway.) The N64 combines the address and data lines, and the mask ROM chips have the appropriate circuitry already designed into them. But for your own cartridge, your best bet would be building a flash cart. Valeriya Pudov designed a flash cart, however the flash chips are out of date (The AT49BV163A is a close match though.) http://web.archive.org/web/20040701140601/gamesys.sourceforge.net/files/MyCart.pdf http://web.archive.org/web/20040701140601/gamesys.sourceforge.net/files/MyCartProg.pdf I'm currently designing a PCB around this with Eagle, but I don't know how far I'll get with it. Maybe someone with more experience and technical aptitude can build one with current parts?
A mask ROM has some type of hardwired bits IN the silicon. They will forever be what they are, not only do Masks have no provisions for erasing, they are just completely different things. EPROM, EEPROM and Flash are very complex analog/digital devices which only a physisist could explain fully. Basically they trap current inside the cells with extremely elaborate systems. BTW, I've got some 16-bit 32mbit EPROM (yay, no interleaving!/ but 5V, ugh!) which I've thought I'd save for a DIY 64M N64 cart (w/ 74 series parts > Since the ROMs decode the memory, I have no idea where stuff goes though.
Mask roms are simple, they only contain enough gates for the 0's ( or the 1's I can't find anything on line that explains it in enough detail ). opr/eprom/eeprom/flash have cells for each bit and you can change a 1 to a 0 electronically, changing back to a 1 depends on the type of device. opr can't be done as it changing to a 0 involves blowing a fuse. eprom is done using light, eeprom and flash are electronicly changed. If I were making one I'd probably use static ram, it's alot quicker and simpler to program and can retain it's contents with a battery. Cost and functionality would probably be the deciding factor. If you are going to program it while plugged in then you can do away with the battery. smf
I don't how you'll manage SRAM for N64 heh. AFAIK, the largest discrete SRAM you can get are 16M at $20+. To get a 512M SRAM card, that's $640 in 32 chips... Pseudo SRAM like 1T-SRAM are the only SRAM option, but I think require custom silicon. Since N64 devices needs logic anyway, may as well create a DRAM refresh FSM to do it's work between the N64's slow accesses.
If you want to have huge amounts then SRAM is less likely to be attractive, but it depends on where you are pulling it from. I was under the impression you could get quite large chips now though, unfortunately components like that are getting harder to find at retail as the money is now in finished products. My interest in n64 would be for running my own code, and I'm unlikely to need much space at all. In fact I might even use a small eprom and then download code into ram & run it from there. Although n64 is a pain because of the lock out chips, or has someone cloned them now? smf
Not that I know of, personally. But you could run your games on the Indy Board. I have one, if you like i can try to run your code on it?
If you're going to do EPROMs, I suggest you interleave 8 bit ones (then you can use EEPROM or Flash), using 16 bit ROMs is SUCH a pain. Like me, you'll need to do MUX/decode logic too.
