Emu XL-7 & MP-7 User's Group

--- In xl7@yahoogroups.com, Matt <somatt@...> wrote:

> > If it stops in the same place or the factory reset takes a long time then
> > you may have a flash memory problem.
> > The unit writes to flash and waits for the chip to return from the write
> > process before writing another byte.
> > Faulty flash may be increasing the write time.

> > The early flash only had about 100,000 writes on average.
> > I'm not sure what the P2k uses but the 100k is an average so there will be
> > some chips that bomb out sooner.

In principle you are right. The flash chip in the XL-7 is an Intel E28F640, which has a minimum specified erase cycle count of 100,000. Note, it's not the average, it's the minimum write cycle count. And that is intended to hold over the entire operating environment range of the chip; it is most likely not operating at its extremes in the XL-7 (for instance, the chip is specified up to at least 70°C, but it never gets that warm inside the XL-7).

Doing the math that means that over a period of 10 years you could write to the same location in memory almost 30 times per day. Even with daily use it is unlikely that someone would manage that. It's not just 30 write operations per day, it's 30 writes to the same patch location every day for 10 years.

So while possible, I'd rule that out. The fact that writing the sysex bank fails even with very long delays (one second per sysex block), and the fact that after having happened once it starts to happen even for the first sysex block received until the system is rebooted, points to something in the software in the XL-7 that can't handle the sysex data. Indeed, the patches that are in fact received aren't playable anyway, and I know that the original author of the files didn't have the possibility to test them, so it seems likely there is an incompatibility in the patch file somehow.

> > You have to be carefully about the sysex in the P2k as it can write
> > directly to the flash RAM and if you are happily changing stuff all the
> > time eventually it will fail.

I don't know how my XL-7 was used before I bought it, but I rarely dump sysex to it. It is a valid point though for someone using a software editor.

/Ricard