nrf52810: HFXO is not turned on as expected

RE: nrf52810: HFXO is not turned on as expected

Håkon Alseth — Tue, 31 Mar 2020 08:41:09 GMT

Hi,

[quote user="SeanKao"]thanks, is there anything I can do to force the HFCLK to work with external 32M crystal? So that I can verify the external 32M crystal is working as expected.[/quote]

You can run this sequence, and if you hang in the while-loop, the hardware has issues with starting up the external HFCLK:

NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

Note that this might be overridden by other modules if they also control the HFCLK directly.

Kind regards,

Håkon

RE: nrf52810: HFXO is not turned on as expected

SeanKao — Tue, 31 Mar 2020 07:52:30 GMT

Håkon,

thanks, is there anything I can do to force the HFCLK to work with external 32M crystal? So that I can verify the external 32M crystal is working as expected.

Regard.

RE: nrf52810: HFXO is not turned on as expected

Håkon Alseth — Tue, 31 Mar 2020 06:30:00 GMT

Hi,

The menuconfig picture is related to the LFCLK (the 32kHz clock source), while the register you're checking is the high frequency clock (HFCLK). The HFCLK will run only when needed, to save power. The system runs on the more inaccurate HFINT (64M RC oscillator) for generic processing.

SoftDevice also behaves like this, to ensure low power consumption.

Kind regards,

Håkon

RE: nrf52810: HFXO is not turned on as expected

SeanKao — Tue, 31 Mar 2020 03:06:36 GMT

I use this example

west build -p auto -b nrf52810_pca10040 samples/bluetooth/peripheral_hr

After west flash I power off and on the board then check the register value, even I wait a few minutes and check the register value again, the value is still the same.