Opta PWM limitations

Official Hardware Opta
1

Hi!
we are trying to use Opta Analog Exp' PWM for driving some heaters at a rather low frequency ~1Hz.
What we observed is that if PWM freq is set below ~50Hz, then PWW 2 and 3 stop working (do not output any signal) while commands getPwmFreqHz and getPwmPulsePerc still show that PWM 2 and 4 is active and PWM 1 and 4 will work fine.
PWM 1 and 4 work fine down to ~1Hz.

This behaviour was tested/could be recreated with standard PWM example code in IDE.

Has anyone observed such behaviour? is it a hardware limitation or some sort of a bug?
What is the lowest freq PWM Opta could handle? (haven't seen it documented anywhere)

Thanks!

1 Like
2

Got some updates on the issue..

Upgrading the firmware for analog extension to latest one fixed the problem, but not entirely.

Now all PWMs (1 2 3 4) can do 1Hz, but if you try 0.5Hz (period = 2 x 10^6 us) only PWM 1 and 4 deliver fine, PWM 2 and 3 stay at 1Hz and deliver 2x higher duty. Apparently pulse setting goes trough but not the period setting.

Would be nice to hear any other experiences on this.

3

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.