Hello, On Tue, Jun 16, 2009 at 6:30 PM, David Hawkins<d...@ovro.caltech.edu> wrote: >> Most MPC8xxx board designs I have seen suffer from this possible dead >> lock: >> - NOR Flash is put in erase mode or write mode >> - Hardware watchdog triggers >> - HRESET# is asserted by the processor, during which the configuration >> words are read from NOR Flash. >> >> Either >> HRESET# is not attached to NOR, NOR stays in erase/write mode and >> invalid words will be read -> dead lock >> >> or either: >> HRESET# is attached to NOR reset, NOR is reset, but stays in reset as >> HRESET# stays asserted. >> >> We have been looking at several solutions hardware wise that reset the >> NOR flash on HRESET# going low, but the processors are stubborn, >> read the config words only once, than dead lock. >> >> I wonder if there are known-working designs for this. > > What do you do in the case of blank flash on a board? > The problem is not with blank flash or firmware upgrades, we know how to handle that.
Your solution is (a solution) to a different problem. The problem lies in the fact that board dead lock can occur if the watchdog triggers, for all reference designs I have seen. Thanks for thinking along. I would like to solve the original problem though. BTW, we use CPLD/FPGAs on most of our boards, this one we do not for cost reasons. Regards, -- Leon _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev