nrf_sdh_enable_request Doesn't Return on a Custom PCBA

RE: nrf_sdh_enable_request Doesn't Return on a Custom PCBA

WestCoastDaz — Wed, 22 Jul 2020 17:53:00 GMT

Thanks for the help!

RE: nrf_sdh_enable_request Doesn't Return on a Custom PCBA

haakonsh — Mon, 20 Jul 2020 14:16:19 GMT

What Hugh already said is true.

Unless you've specifically start the LFXO through the clock driver/HAL the RTC will use the LFRC as the source.

[quote user=""]Is there a method to confirm the crystal is oscillating?[/quote]

Use the CLOCK driver to start the LFXO:

nrfx_clock_init() -> nrfx_clock_lfclk_start() -> while(!(nrfx_clock_lfclk_is_running())){ //Do nothing, block until LFXO starts}
Scope the crystal's pins with an oscilloscope.

RE: nrf_sdh_enable_request Doesn't Return on a Custom PCBA

hmolesworth — Fri, 17 Jul 2020 23:55:55 GMT

"If the LFXO is selected as the clock source, the LFCLK will initially start running from the 32.768 kHz LFRC while the LFXO is starting up and automatically switch to using the LFXO once this oscillator is running. The LFCLKSTARTED event will be generated when the LFXO has been started."

I think the SoftDevice monitors LFCLKSTARTED whereas RTC does not; this suggests as the RTC works that the 32kHz crystal never starts oscillating, usually a load cap issue.