SRAM speed question please

[Markfrizb]

Can SRAM speed be too fast for the Snes? If so, what is the speed limit?

I'm looking at some replacement SRAMs for the cartridges and the SRAM I'm considering is rated at 15ns. Is this ok to use (speed wise)?

Thanks!

[koitsu]

AFAIK there should be no problem using chips that run faster than the minimum required by the console.

[Memblers]

I have no idea about SNES, but I do know on NES there can be issues with fast memory. During sprite DMA, seems almost like the data is enabled before the DMA is finished or something, the result I've seen is a few corrupt sprites. It's fixable by putting some resistors in series with the data bus. SNES DMA might work differently and be fine, but that's the area that I would say to investigate.

[whicker]

No real speed limit, but depends on how good the chip select logic is.

Since the address lines won't all change at the same time, if CS bounces up and down a few times before settling low, that SRAM chip is reactive enough to get more than a few writes to semi-random places.

There's really no advantage of using a faster chip. But of course I suppose anything 200-120nS is going to be pulls from old equipment.

Also, are you talking about real asynchronous parallel SRAM? Nothing weird like some NV RAM where it latches the address on the falling edge of CE or OE ?

[Markfrizb]

nothing weird or special. Just looking at SRAM possibilities for a cartridge I am making.
http://youtu.be/9-FtbGnAzEo?list=UUnk4F ... lUugXkVvPA
I found some cheap ones running at 15nS. Just wasn't sure if it was too fast... think the original ones are 55nS or around that....

Thanks for all the input!