libpruio: How to Turn Off PWM?

[Don Pancoe]

I have been making good progress with learning and using libpruio, but I've hit a question I've been unable to work out for myself.

I've successfully started PWM signals using pruio_pwm_setValue(), but I'm having an issue turning those same PWM signals off when I'm done with them. I've tried using setValue() again with zero values for frequency and/or duty cycle, and my DMM (which can measure such things) is reporting zero frequency and duty cycle, but it is also measuring a constant 3v3 output on that header pin. Effectively a 100% duty cycle, which my DMM would actually report as zero frequency and duty cycle.

Is there anything I'm missing here, or are there better ways to turn off the PWM signal in libpruio?

FYI, I have a Beaglebone Black, Linux 4.14, Debian 6.3, but I've noticed more libpruio discussion on his board. I can also post any additional information needed.

Thanks,

Don

[Don Pancoe]

Using pruio_gpio_setValue() to set a value of zero seems to do the trick, but I'd still be curious to know if there is an "official" way to do this.

Don

[TJF]

Hi Don!

Am Mittwoch, 13. März 2019 21:49:06 UTC+1 schrieb Don Pancoe:

Using pruio_gpio_setValue() to set a value of zero seems to do the trick, but I'd still be curious to know if there is an "official" way to do this.

Setting the duty cycle to zero is the official way to switch off PWM output. (Note: switching off by setting the frequency to zero would be dangerous, since it will set the frequency for both outputs A and B in case of output generated by a PWMSS subsystem. That's why such a feature isn't implement.)

Regards

[Don Pancoe]

Thank you for the reply! So far, pruio_pwm_setValue() with a non-zero frequency and zero duty cycle definitely seems like the most stable way to stop a PWM signal.

Don

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