Dephasage on PWM

[EliasAd]

Hi,

I want to ask you, if they're any phase locked loop (PLL) that can be used ? 

My problem : I have two square signal generate by an Arduino Nano and a PWM on the nordic and I wanted to synchronise them (they have the same frequency). I tried with the function delay without success.

If you have any solutions, thanks in advance.

Best Regards.

[Sigurd]

Hi,

An option could be to capture the PWM from the Arduino on one of the GPIOs on the nRF52, then use PPI to start the PWM on the nRF52 when you get a GPIOTE event(falling or raising edge).

[EliasAd]

I just tried it. It almost work. Do you know if I disable the pwm and then enable it, The PWM will continue from it previous state or restart as a new one ?

[Sigurd]

EliasAd said:

The PWM will continue from it previous state or restart as a new one ?

It will restart, but you can configure if it should start high or low.

EliasAd said:

It almost work

 Almost ?

Could you post some code on how you did it ?

[EliasAd]

 if(!nrf_gpio_pin_latch_get(PINTRANSZERO)){ //Sense_LOW of the pin
    if((previous_state)){
      count++; //count number of falling edge
    }
    nrf_gpio_pin_set(LED3);
    previous_state = 0;
 }else{
    nrf_gpio_pin_clear(LED3);
    previous_state = 1;
 }
 nrf_gpio_pin_latch_clear(PINTRANSZERO);

I done this for detect a falling edge.

Where can I find an example of the configuration of the start. 

[Sigurd]

Are you using the PWM driver or the PWM library ?

[EliasAd]

The PWM Library

[Sigurd]

For PWM synchronization use-cases, it’s generally better to use the PWM driver (easier to use PPI with the PWM driver / dedicated PWM peripheral). The connect GPIOTE event with PWM TASKS_SEQSTART[0] task. Here is link to PPI driver doc. If you don't use the driver, it's also possible to do it bare-metal, see this example.