nrf52810 PWM issue

RE: nrf52810 PWM issue

WrightLin — Mon, 13 Aug 2018 03:25:34 GMT

Thanks for your help.

our customer is trying to use PPI methods to solve their problem.

RE: nrf52810 PWM issue

Mahesh Venkitachalam — Wed, 08 Aug 2018 05:49:24 GMT

I don't think you'll have a problem with softdevice. You can see the softdevice documentation to see which peripherals are in use. As long as you use others (and there are plenty left) you should not have a problem.

"The Programmable peripheral interconnect (PPI) enables peripherals to interact autonomously with each other using tasks and events independent of the CPU."

So this is designed exactly for what you're doing. An external signal can control PWM with minimal CPU involvement.

RE: nrf52810 PWM issue

WrightLin — Wed, 08 Aug 2018 05:43:54 GMT

Hi Mahesh:

Got it , thanks for your suggestion.

Do you have any idea about whether the external signal be interfered by softdevice or not?

RE: nrf52810 PWM issue

Mahesh Venkitachalam — Wed, 08 Aug 2018 05:28:44 GMT

I think your GPIOTE idea is correct, but you should just use the external pin trigger to toggle PWM on/off in the handler. The PWM itself should be configured separately. You also have a 1ms delay in your gpiote handler, which might be a bad idea.

RE: nrf52810 PWM issue

WrightLin — Wed, 08 Aug 2018 05:14:03 GMT

Hi Bui:

we are trying to make PWM pulse , and it's controlled by an external signal "ZeroX".

To be more precisely, when we detect there is a rising/falling edge of ZeroX , we trigger nrf52 to generate PWM pulse.

It's a known issue that Softdevice will interfere the process of PWM generating.

So, when generating PWM pulse , we should use PWM driver to avoid interference , right?

But the controlling signal -- "ZeroX" which is also an external signal .

We're wondering if it will also be interfered by softdevice.

If it will be interfered , then how should we do to avoid this situation ?

RE: nrf52810 PWM issue

Hung Bui — Tue, 07 Aug 2018 14:17:24 GMT

I'm not sure what you are trying to do. Could you please explain ? What is generating the duty cycle ?

RE: nrf52810 PWM issue

WrightLin — Tue, 07 Aug 2018 09:25:19 GMT

Hi Bui:

Does the gpiote_event_handler() code illustrate the concept you need?

RE: nrf52810 PWM issue

Hung Bui — Tue, 07 Aug 2018 09:04:49 GMT

Hi, could you explain a little bit more ? You mean you flip the GPIO pin based on the input from IO_ZERO_X ? Like cloning the signal ? And there is no timer ?

RE: nrf52810 PWM issue

WrightLin — Tue, 07 Aug 2018 08:59:25 GMT

Hi Mahesh & Hung:

I have updated the code of generating PWM , please kindly check it. Thank you!!!

RE: nrf52810 PWM issue

Hung Bui — Mon, 06 Aug 2018 12:30:54 GMT

@WrightLin: Please provide the code you used. You mentioned "When I simulated PWM by GPIO " did you use software to generate PWM ? Can you just use the hardware PWM we have ?

RE: nrf52810 PWM issue

Mahesh Venkitachalam — Mon, 06 Aug 2018 08:13:08 GMT

Are you using the PWM library? Maybe share some of your code that's generating the PWM?