BLE not advertising on Custom board.

[David]

Good day,

I have a problem with a custom board I have designed. It does not advertise the BLE device when programmed. I am testing with the simple ble_blinky and the nrf_connect mobile app. I have designed multiple NRF52 custom boards in the past and they have worked flawlessly. The only difference in this new design is that I have added the 32.768 Khz crystal connected to XL1 and XL2. 

Here is the crystal I am using.

The usual 32 Mhz crystal has also been connected to XC1 and XC2.

In the SDK config, I have tried setting NRF_SDH_CLOCK_LF_SRC to 0 (which corresponds to NRF_CLOCK_LF_SRC_RC). I have also tried setting it to NRF_CLOCK_LF_SRC_XTAL and NRF_CLOCK_LF_SRC_SYNTH but no solution works.

Please what could be the problem, is there any special change I need to make when using the 32.768 crystal.

I am using SES and I think it flashes the softdevice on each upload.

[Kenneth]

I don't expect that the 32kHz is the problem here. Likely the problem is the 32MHz or a design issue. Have you run for instance rf test or DTM to verify carrier frequency?

Best regards,
Kenneth

[David]

Hello Kenneth, I haven't done this. Can you give me more details about this?

Also, the code hangs when I add this line:

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

I have tried swapping the crystal but still not result. Here is the 32MHz crystal I am using.

https://lcsc.com/product-detail/SMD-Oscillators-XO_KDS-Daishinku_1XTV26000PEA_KDS-Daishinku-KDS-1XTV26000PEA_C253733.html

https://datasheet.lcsc.com/szlcsc/1810221841_KDS-Daishinku-1XTV26000PEA_C253733.pdf

Its the same datasheet, just a 26MHz version. Please Is there any other reason why it may not be starting?

[Kaja]

Hi David, 

could you please share the schematic and layout files? Obs, this is a public ticket, so if you want that information to stay private, please change the case to private.
Also could you tell me the load capacitance, CL, of the 32 MHz crystal your using? 

Best regards,
Kaja