nRF52832 doesn't seem to boot

[rboutrois]

Hi,
We recently made a custom board for a new project, based on the nRF52832-QFAA.
Everything looked fine in the first place as the nRF is perfectly recognized on a PC and can be flashed using nRF Connect via a nRF52 DevKit.
We even can switch the state of the LED on pin 7

So we tried to flash our custom firmware with bluetooth and serial communications (which are working well on the DevKit) but we have no sign of life coming out of our board, neither form bluetooth or serial

Our first guess was at the beginning we didn't soldered L2, so we forced the LDO in the software but nothing changed.
Then we soldered L2 to use the DCDC : nothing
We even added the small 15nH in series to L2 : still nothing

The next guess was for the bluetooth and the antenna matching, so we did the best we can to tune it but the board is still silent.
Can a bad antenna tuning can fry some specific parts of the chip ?

I joined the schematic corresponding to the nRF part of our board to let you check if we missed something.

Any help will be highly appreciated, thank you.

[JONATHAN LL]

Hi,

Are you still able to program the chip? you can toggle a LED ?
 

an a bad antenna tuning can fry some specific parts of the chip ?

 If you somehow ended up using to much heat and damaging the SoC it should not be a problem. 


Can you share the complete schematic and PCB layout files(Gerber) ? I can make this ticket private if you dont want so share any info.

Do you have the HFXO and LFXO mounted?


It can operate in LDO mode as shown in the ref design https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/ref_circuitry.html?cp=4_2_0_52_0#schematic_qfn48_ldo 

Regards,
Jonathan

[rboutrois]

Hi Jonathan,

Thanks for your reply

Programming the chip and toggling a LED are mostly the only things we can actually do with our boards.
We assembled 4 of them and they have exactly the same issue.

We respected the reflow temperature curves and the chip doesn't become warm when using RF.

I can share you our design files, but as proposed, we prefer to make the ticket private if possible.

We just figured out we inverted HFXO and LFXO in the schematic, so on our board as well ... That can explain why we only have only "basic" function.
Unfortunately the crystals don't have the same footprint so we have to remake a new PCB to resolve this problem.

[JONATHAN LL]

Thanks for updating the post with the solution.

Regards,
Jonathan