Hi all,
a few weeks ago I posted a problem I have with AT89S8252 flash
memory. I have a 4700µ condenser connected to Vcc
(4 NiMh batteries 5.6V max - 4.8V min) and if I remove
power and immediately reconnect it (happens e.g when someone
is trembling while connecting the batteries/supply) the 89s8252
"forgets" its flash memory, means it doesn´t start again !!! and has to be reprogrammed with a parallel programmer.
Peter Dannegger convinced me to add a supervisory/reset circuit
and so I added a MAX810 (V reset=3V)
which does a nice job so far BUT the
89s8252 still looses memory contents from time to time (not always).
Not just one but a whole bunch of chips I´ve tested so far.
Unfortunately I cannot tolerate any memory loss in a medical device.
I contacted another user with similar problems.
Since this happens only occasionally (still too often) I don´t think the problem is too much software related.

Did anyone experience the same/similar problems.
Any solutions ?

Thanks a lot,
Karsten