exxos wrote:Some sites listed them as FPM, some didn't. Same with some datasheets. So wasn't really sure either way, so thought I would just try them and see.
The Huyndai (?) datasheet confirms that these are FPM. I think virtually all 30 pin SIMMs have FPM-DRAMs. Also, I don't think I've ever come across a 1Mb SIMM that does not work in my STE. On the rare occasion when a SIMM does not work, it always has a sibling that does work. I.e. the non-working SIMM is broken, not incompatible with the STE.
exxos wrote:I know people have said FPM works, but the stack of them I have here didn't work. I just got all kinds of crazy on the screen and just gave up with them.
Do you happen to still have them? If so, could you list the DRAM part numbers? Maybe they were too slow?
joska wrote:That's not exactly correct. It depends on the DRAM. Generally speaking they don't do any harm, *if* the logic floats high and is stable, but its not always the case. Generally parity chips should be avoided, or the parity chip taken off, which is what I have been doing.
I'm sorry, but this does not make sense. There is nothing magical about parity. It's just a ninth bit, the value is computed by the DRAM controller if it supports parity. If not, it just does not read or write this bit. It does not affect the data bits at all.
Atari themselves shipped their STE's with parity RAM. I've got a bunch of 256KB SIMMs here from upgraded STE', all of them have parity bits.