AVR-Chat

I'm having an oscillator problem with a Mega162 device ... Dunno if
anyone has seen it before and might have some advice.

I've got 4 identical units with Mega162, 16MHz xtal with 15pf
capacitors. One of them will not start up on power up (no oscillator)
but the others are fine. If I reprogram the chip in the non-working one,
it then works fine for the rest of the day, power on and off as much as
you like, but the next morning when I come in, it does not work again.

Now I've had this situation before with some units using the Mega8, and
it turned out to be because I had not set the CKOPT fuse bit on the
Mega8. This changes the mode of the oscillator to give larger
oscillations. With CKOPT unprogrammed, they mostly worked but the odd
one failed to start on first power up as described above. With CKOPT
programmed everything was fine.

Unfortunately the Mega162 does not seem to have a CKOPT bit - any ideas
what I can do to the oscillator circuit to make it work reliably?

-- 
Tim Mitchell
tim@sabretechnology.co.uk
http://www.sabretechnology.co.uk