nRF51822 custome board crystal problem.

[Anton]

Hello,

My nRF51822 custome board has problem at first programing software with nRF51 DK. So I checked nRF51822 boot sequence and found diffence compare with nRF51422 which is in dev board.

<Difference with referecence board,nRF51 DK >

• 16MHz crystal is not running in 3.2V VCC input. I found that from Analog input/ouput pin (pin#37 and 38).
• There is not clock in SWCLK pin.

So my question are belows:

• Does 16MHz crystal possible to not running with 3.2V VCC?
• How can I verify QFN part is right soldered in custome board? As I know that can be checked by crystal clock. Anything else?
• Does nRF51822 working with particular 16MHz crystal? I choesed NX2520SA ,NDK, which is already confirmed in dev zone comment.

Of course I followed reference schematic and layout refer with 'QFAC QFN48 schematic with low voltage mode' from spec.

Thanks,

Anton.

[Stefan Birnir Sverrisson]

Hi Anton

Make sure you have valid load capacitors for the crystal. A guide for calculating appropriate values is given on this thread.