If EVENTS_HFCLKSTARTED never triggers is the problem definitely pcb related?

Question

Hello All, 
 We have a custom board with nRF52840 and I believe, we have problem with the HFCLK. 
 We are trying to test our board with the ble_app_blinky example and it works fine with our nRF52840 Preview DK. Using the same example on our custom board, the ble_stack_init() function hangs and ble never initialized. When I put the below code at the start of my main function, the code just hangs in the while loop. I also read that the radio module on the chip requires the external HFCLK source and without it we cannot use BLE functionalities. 
 NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0); 
 I've read many threads in this forum releated the HFCLK not starting issue and almost all of them was related to PCB soldering or some other PCB design problems. We are using the reference design shown below and our IC revision code is nRF52840-QIAAC0. HF crystal orientation looks correct in our PCB but we haven't tested everything yet. So do you think our issue is related to the hardware(pcb)?

Thank you very much for your help in advance.

RK · Accepted Answer

If you're correct about the crystal which has been mounted then .. it's not even a crystal, it's a crystal oscillator designed with the same form factor as a 2mm x 1.6mm crystal. That thing requires power into pin #4 which I'm 99.999% you've grounded as pins #2 and #4 are ground on a real 2x1.6 crystal. It would actually be possible to use a crystal oscillator such as this one as the nRF does accept a driven oscillator input, however you'd need a different circuit to apply power to it and you'd need different settings on the nRF to use it. 
 I don't know why anyone would replace the crystal you specified with an entirely incompatible device. But it's not going to work.

If EVENTS_HFCLKSTARTED never triggers is the problem definitely pcb related?

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