Hi All,
Sorry this is a SNES related question.
Is it possible to find a generic ROM/PROM that can be programmed and used to replace the SNES Mask ROM in a SNES cartridge?
I have looked at using EPROMS but it looks a bit messy.
Thanks for any ideas!
Most likely not, unless it's a very small game. Larger EPROMs are 27C4001 who are 512kB (4 MBits) or the rare 27C8001 who are 1 MB (8 MBits).
Only a handfull of SNES games are 2 or 4 MBits, but I guess that there is plenty who are 8MBits, unfortunately the corresponding EPROMs are rare, and the pinout is not compatible anyway so some rewiring should be needed.
Just like the NES you have two options. Bending up pins that don't match the pinout and running wires around, or cutting traces on the board and running wires so you can solder the chip directly to the board. I like that idea better myself. Also, TheDumper made a program that will swap address lines for you in the ROM image before programming that reduces the amount of rewiring needed. It's called SwapBin.
MottZilla wrote:
Also, TheDumper made a program that will swap address lines for you in the ROM image before programming that reduces the amount of rewiring needed. It's called SwapBin.
Got a link to this tool.
MottZilla wrote:
http://www.ultimate-console.fr/index.php?option=com_remository&Itemid=46&func=select&id=6
Thanks I'll have to check it out.
or try this one (same codebase, just much nicer
)
http://www.romhacking.net/utils/593/
Anyone have an idea why mask ROM pinouts are different from EPROM pinouts?
Pins are one of the most expensive things on a packaged integrated circuit. They need to be inserted into the package, routed to the circuit, and buffered inside the circuit. In fact, some of the limitations of the NES PPU and the MMC1 are due to pin count optimizations.
Mask ROM needs address lines, data lines, 0 V, 5 V, and chip enable. The 28 pins on a DIP-28 package provide 17 address lines, or 128 KiB. EEPROM, on the other hand, needs things like a write-enable line and a separate programming voltage. That pushes the signal count for that size up to 30, and the corresponding DIP package (DIP-32) is slightly more expensive.
Quote:
Pins are one of the most expensive things on a packaged integrated circuit. They need to be inserted into the package, routed to the circuit, and buffered inside the circuit. In fact, some of the limitations of the NES PPU and the MMC1 are due to pin count optimizations.
So why wasn't the epoxy blob technique the most commonly used by Nintendo ? As a plus it's a big annoyance to reverse-engineers. (sorry for getting off topic).
Bregalad wrote:
So why wasn't the epoxy blob technique the most commonly used by Nintendo ?
A few of the games that Nintendo wanted to replicate
really cheap in
mass quantities were glop-tops. Some of these were pack-in multicarts such as SMB1/Duck Hunt, SMB1/Duck Hunt/World Class Track Meet, Super Spike V'ball/World Cup.