On Sat, 23 Apr 2011 17:58:22 -0700 (PDT), Jeroni Paul
wrote:

If it were easier to remove the crystal I would have already tried a
lower frequency one but it is sandwiched under the VFD panel. I tried
to put a lower frequency crystal in parallel to the current one but it
makes no difference, maybe the current one has lower impedance? Anyway
I think lowering the frequency will break programmed recordings which
is one of the interesting features of this decoder, since the Atmel
keeps a clock and at least the time it has to power on to start a
recording (I believe programmed recordings work this way since it is
the only alive processor while in st-by). By the way, when it awakes
to perform a programmed recording it has the same reboot behavior.

Hmmm. May have to sleep on this one.

Does the processor's oscillator stay running while the device is in
standby? The 89S52 does have a sleep mode where it turns the oscillator
off but if it is responsible for waking up the rest of the device then
I'd guess that it must stay running.

If the oscillator stays running, given that the problem behavior also
occurs when it goes to wake up the rest of the system from a state where
it itself has already initialized, then it does sound like a firmware
problem. Might be something like: wait for N timer ticks and if X has
not happened then perform error recovery; but the actual time between N
ticks can range from (N-1) to (N+1) if the waiting started just before
or just after a tick event.

--
Rich Webb Norfolk, VA