teaguecl wrote:
Sorry, I wasn't clear with my response. Most EEPROM cannot be programmed in-circuit without providing a programming voltage, which is usually very high like 12v. Most flash can be programmed at Vcc in-circuit. This is very handy because you can create parallel port cable to connect to your PC on one side, and the cart connector on the other, and re-program your flash without even opening the plastic cover on the cart (and without a programmer). I don't think this is possible with EEPROM, though I have to admit I gave up on EEPROM many years ago so maybe they have gotten more advanced.
You are absolutely right that flash is much cheaper, and with EEPROM going the way of the dinosaur also much easier to obtain.
Yea
EPROM generally have a 12.5 Vpp but I've never seen a single EEPROM requiring a programming voltage, they're as easy to program as SRAM. I actually prefer them to Flash for minimalist jobs since they can just be written to at the byte level, no dealing with commands or sector nonsense ;)
Bregalad wrote:
Okay. So :
- Is the pinout of a flash compatible with EPROM standards ?
- How easy is to re-programm it from a PC like you said (and like Atroh did on his flash project)
- What is the max size of flash available (EPROM is 2 MegaByte, so it can become short for 4 MByte or 6 MByte SNES games, a combination of chips are needed). Also EEPROM is 32 Kbyte max. so only NROM and CNROM board will work with them.
Yes, all IC with JEDEC pinouts should be similar or identical for transparent use. The largest common 8-bit EPROM I know of is the 27c320 which is 32mbit. EEPROM can be far more than 32kbytes, I know there are 4mbit EEPROM (28c040) and there are likely some obscure ones even larger.