[EE]: Reset problems - 8535
Attila Muhi email (remove spam text)
I have ok crystal cap:s, around 20 pF. The leads from the crystal are as short as they can be, connected to the caps on their way.
DVcc is decoupled very near the chip, so is AVcc. AVcc is normally switched off, and is only switched on by a command from the LS8535 for power saving reasons.
Normally the circuit is in power down mode, with Xtal stopped. It is woken up from sleep by IRQ:s and then put back to sleep again after IRQ service. That works excellent - if the reset goes ok, and the cpu doesn't get stuck.
I realy have no idea of what the CPU is doing when it hangs after a failed reset. There's no entry at all in the code that could cause that behaviour.
Yes,the xtal osc IS running when the cpu is stuck. A nice, good-looking sine-wave, I checked it with the scope. 3.58 MHz by the way.
The dongle can always communicate with the CPU. The result of the reset from the dongle is similar to a manual reset.
I hope I haven't blown it with ESD !
Attila Muhi - SM4RAN
Från: David VanHorn <CEDAR.NET> dvanhorn
Till: MITVMA.MIT.EDU < PICLISTMITVMA.MIT.EDU> PICLIST
Datum: den 12 mars 2001 22:17
Ämne: Re: [AVR]: [EE]: Reset problems - 8535
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