Custom waveform generation in two pins

[Hu Lao]

Hello,

Considering the waveforms in the following chart, which will be the best approach to keep the power consumption as low as possible?

Specifically, which peripheral is suggested (i.e. pwm, timer, ppi)?

The two (2) waveform are identical, except for the delay between (0 to 2ms).

Thanks

[Hu Lao]

Hi haakonsh, I worked on the period counting using the timer and compare function. The implementation worked as suggested. Thanks again for that!

I only have the issue about the initial pulse width, which is around 1ms, when I need 0.1ms. Do you think, there is a way to reduce that pulse width? In case not, the PWM will be the only solution?

The application could have an error in the pulse width of ~30us, but in this case the error is around ~1000us, which is too much.

Thanks

PS: I deleted the previous reply because was a false positive (I didn't fix the initial pulse width)

[Dmitry]

You can configure RTC to clear with the end of second channel pulse and set initial level to 0 for both channels, so your sequence will be aligned to the end of period (there will be some delay before the first pulse though)

[Hu Lao]

Hi Dmitry, thanks again for your feedback. Your suggestion is great. In this application the position of the first pulse could be delayed at the beginning. 

I just implemented and is working as expected. Below the waveform for future reference. 

Regarding the other two segments (OFF left and OFF right) do you have a suggestion, again trying to keep the power as low as possible? 

Thanks

[Hu Lao]

Hi again, just a small note to mentioned that the phases OFF (pre and post) were implemented using the app_timer. Perhaps, using the RTC with a comparator (+interruption for setup ON phase) will be a better approach for power consumption but I still need to check overall resources.

In any case, the phase ON was very power sensitive.

Thanks all for your feedback!