Can't discover NRF52832

[Bikti]

Hi. 

We have a debug board for the NRF52832. The breadboard on this board is working fine. But if NRF52832 is used outside the debug board, then for some reason, some phones cannot detect the device. The firmware for both boards is exactly the same. It was also not possible to detect the device through the "NRF Connect" app, restarting the smartphone did not help.
List of smartphones that can detect the device:

• iPhone 7 Plus (iOS 14.2)
• iPhone 10 (iOS 14.2)
• Samsung Galaxy S7 (Android 8.0)
• Samsung Galaxy Note 8 (10.0)
• Xiaomi Redmi Note 7 (Android 10.0)

Connection and exchange of packages works normally

List of smartphones that could not find the device:

• Xiaomi Redmi Note 8 Pro (Android 10.0)
• Samsung A50 (Android 10.0)
• Oppo A91 (Android 10.0)
  
  

[Simonr]

Hello

This sounds like an issue caused by a bad/mismatched 32MHz crystal on the custom board(s), as different mobile processors have different requirements for how accurate the frequency is for them to pick up the signal properly. Can you provide a schematic of your nRF52832 showing how the 32MHz crystal is connected in particular, the capacitors you are using here, as well as the datasheet of the 32MHz crystal you're using.

Best regards,

Simon

[Bikti]

Thanks for the answer. We have already fixed the problem by taking a crystal resonator from the debug board. Your answer is correct.