I would guess that the inductance of the motor parts has caused a voltage transient on your timer port pins. I would have to see the schematic to guess how that is happening. Feel free to send it to me to look at.
I would be very suspicious of having a burnt-out microcontroller in a motor drive circuit. If it happens in the lab, it will surely happen in the field. Blake On Wednesday 16 January 2008, Shashank Chintalagiri wrote: > Hi > I've got some strange problem with the timers on an atmega16L. I'm > using timer1 to produce two pwm signals that go on to some other > circuitry that in general should not be drawing much current, and > certainly not more than say 10 mA. The pwms seem to be working fine as > long as the attached circuitry (in specific, a motor driver) is > powered down and I see the variation in voltage with pulse width as > expected. However, once the rest is turned on, the pwm outputs both > jump to 5v. I _think_ it used to work for sometime earlier before > going to 5 volts, but I cant say that for certain. Now the correlation > between the turning on of the switch and the change in the output of > the pwm pins is impossible to ignore. > > Also, replacing the atmega with another one, it seems to work just > fine. I'll do some more testing to see if this one also starts > behaving this way after some use, but as of now it seems to be more > stable than the other one. The new atmega happens to be an atmega16 > (as opposed to the 16L used initially). I dont see how that would make > a difference in this case, though. Both are using the internal > oscialltor. > > Any ideas on what may have happened? Does anyone know of an atmega > getting damaged/behaving in this way? Most importantly, should i worry > about the same thing happening to next one also and make some changes > to the rest of the circuitry. > > Thanks > Shashank _______________________________________________ AVR-chat mailing list AVR-chat@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-chat
