Don Miller wrote: > It it safe to cut the power at any time? Alas, it may be unsafe to cut the power at any time ...
I think what you experienced was the NOR corruption issue. Every time you cut power of an M1rc3 device, there's a small probability of the NOR Flash getting corrupted. In my experiments, I got a probability of about 1:500 without locking (see below) and estimate a much lower probability (maybe 1:100000) with locking. I'm not sure whether the dramatic circumstances of your power-down had any effect on the corruption. Chances are it was pure coincidence. The corruption is caused by the NOR still being powered while the FPGA is already in an undefined state. There is a reset chip that should protect the NOR in such situations, but the way it's used in M1rc3, it reacts far too late. As a band-aid solution, one can lock part of the NOR. The locked area includes the blocks most likely to get corrupted. Recent versions of m1nor and reflash_m1.sh should do the locking automatically, so you're probably safe now. There's also a script (dumplock) you can use to check that the first 55 blocks are properly locked: https://ssl.serverraum.org/lists-archive/devel/2011-October/002432.html There's still a small risk that the M1 could unlock the NOR on its own, but the probability for this should be very low, see section "Invulnerability debunked" in https://ssl.serverraum.org/lists-archive/devel/2011-October/002465.html Unfortunately, a proper fix would involve non-trivial hardware rework: https://ssl.serverraum.org/lists-archive/devel/2011-October/002505.html - Werner _______________________________________________ Devel mailing list Devel@lists.milkymist.org https://ssl.serverraum.org/lists/listinfo/devel
