Actively toggling HFXO when using Soft Device

RE: Actively toggling HFXO when using Soft Device

Vidar Berg — Thu, 29 Jul 2021 11:36:06 GMT

"immediately" is maybe not entirerly accurate. Like you said, stopping of the HFXO has to be delayed if the application releases the clock request while the clock is in use by the Softdevice (Softdevice does handle this scenario).

RE: Actively toggling HFXO when using Soft Device

Brian Shankland — Thu, 29 Jul 2021 11:21:02 GMT

Thanks for confirmation Vidar.

Documentation for release says that the HFXO is stopped immediately, but I'm assuming that if the Soft Device is also using it that this will be delayed until it is also finished.

I will check that HFXO is running when I request it, but will not check for it stopped on release - let Soft device decide when it is safe to do so.

Thanks,

RE: Actively toggling HFXO when using Soft Device

Vidar Berg — Thu, 29 Jul 2021 11:12:04 GMT

Hello,

Yes, the Softdevice include APIs to both request and release request for the HFXO. The Softdevice won't turn off the crystal as long it's being requested by the application.

Relevant Softdevice functions:

- sd_clock_hfclk_request

- sd_clock_hfclk_release

- sd_clock_hfclk_is_running

Best regards,

Vidar