About NRF52832 PWM output accuracy and pin problem?

[creator]

How do you do 1.Now want to set the PWM output frequency is 60 hz, but with an oscilloscope test is 60.24 hz, here more than 0.24 hz.How can I do the precision of the precision of 0.01 hz or 0.05 hz? Procedures and oscilloscope is as follows: top_value=500KHZ/60HZ=8333

2.Configuration PWM output pin, it found that not every IO pin can, such as the above procedures in IO mouth only high level 6, there is no PWM, also found 9.10 pin is not PWM output, right?This how to solve？

[creator]

NRF_CLOCK->TASKS_HFCLKSTART = 1; while(!NRF_CLOCK->EVENTS_HFCLKSTARTED){}

[Sigurd]

Hi,

1. That is correct. You need to start the HFCLK crystal oscillator with the TASKS_HFCLKSTART to get more accuracy in the PWM signal.

2. Some GPIO pins on the nRF52-DK are used for other things, e.g. LF-Crystal, buttons, leds. Pin 9 and 10 are used for NFC by default. See this page for a drawing.