> Hi, > > is it possible to use pwm on micaz within tinyos? > are there free timers for pwm? > > > thx > Anton
Yes, the ATMega 128L used in the later mica* motes can generate several PWM signals. You'll probably have to access the hardware directly; I'm not aware of any TinyOS abstractions (previous to 2.0) that offer detailed enough control over the counters to allow useful PWM generation. 2.0 may have improved some, but it probably depends on whether you need more exotic features like variable frequency or phase-correct PWM generation. The tricky part I found was in working around the TinyOS counter usage, since the radio component in particular has to have a timer. On the Mica2, which is pretty similar to the MicaZ, I found Timer0 was the hardest to work around, and Timer2 is reserved in the hardware design, so you can't use it under any circumstances. Timer3 seems to be the safest to use, though Timer1 appears to be fairly unmolested by most TinyOs functions too. Fortunately, 1 and 3 are the more sophisticated high resolution timers, so they can do about anything that Timer0 or Timer2 can. In my app, I actually managed to do phase-correct variable frequency PWM for a PD controller, counter driven 6 kHz ADC, and frequency measurement at the same time, so they can be fairly flexible. Just remember to restore all the counter registers after you're done with them. See http://www.avrfreaks.net/index.php?module=Freaks%20Devices&func=displayDev&o bjectid=55 For hardware details. Ben Buckner _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
