[Tinyos-help] PWM on micaz

[Michael Schippling]

I have some limited support for ATMEGA PWM here:
http://www.etantdonnes.com/Motes/AVR128timers.zip
MS


Ben Buckner wrote:
>> 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
> Tinyos-help at Millennium.Berkeley.EDU
> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help