Hello everyone,
I am having some trouble starting the HFXO crystal manually before using the RADIO to send raw advertisements: the HFCLKSTARTED event never raises. The code used to start the HFXO is:
NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) {}
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
But the execution stalls in the while loop because the event HFCLKSTARTED is never raised. After reading a few posts with people who had similar issues, here are the things I tried so far:
- Tried to remove the while loop to see if the radio would work: it does not
- Changed crystal and its capacitors. The crystal used is 8Y-32.000MAAV-T and the capacitors are 12pF NP0 2%. We followed the Nordic layout guidelines.
- Probed the crystal pins: the scope gives correct waveforms so it is defenetly not a soldering problem of the nRF52840.
- Ensured that the 1uF capacitor at DEC4 pin is soldered properly
- Tried our code on a different board: the code works flawlessly (with the while loop)
- Tried a Nordic example (ble_app_beacon for instance) with SoftDevice: the advertisements are sent correctly.
The last point is what baffles me the most. According to this post, it is mentionned that the Softdevice will always start the HFXO before a RADIO event, which totally makes sense since it is mandatory for the RADIO to work. However, if the softdevice is actually able to start the HFXO to send advertisements, why it doesn't work when using our code (without softdevice)?
Our code is not the cause of the problem because it was tested successfully on a different board. I am tempted to say that the board is not the problem also because it works when using a Nordic example.
I must be missing something. Any help would be greatly appreciated.