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NRF52832 custom board can be connected by NRF dongle but cannot identified by phone

I have made a custom board using NRF52832 (NRF52832-QFAA-R/QFN-4) with 32MHz and 32.768 kHz crystal. The SDK is nRF5_SDK_17.0.2_d674dde. It can be connected using nRF52840 Dongle ( https://twcn.rs-online.com/web/p/wireless-adapters-wifi-dongles/1769054 ). The blinky peripheral can connect and toggle the LED. But the custom cannot even be scanned by NRF connect on the android phone (Sony Xperia 5, Samsung A20 SM-A205GN, Sony X Compact F5321, Sony XA1 G3125). The same program and softdevice put on SparkFun nRF52832 Breakout (https://www.sparkfun.com/products/13990) can be scanned by dongle and phone. I have also try to bypass the regulator and give 3.3 V to NRF. But the problem is still there. Does anyone know what this problem can be?

Schematic (Core)

Demo (connect by dongle)


Key component list
QANTEK 32MHz Crystal ±20ppm SMD 2-Pin 5 x 3.2 x 1.1mm ( https://my.rs-online.com/web/p/crystal-units/813-6148/ )
TXC 32.768kHz Crystal ±20ppm SMD 2-Pin 3.2 x 1.5 x 0.75mm ( https://my.rs-online.com/web/p/crystal-units/753-7265 )
Antenna: YAGEO CAN4311153002451K (http://www.farnell.com/datasheets/48853.pdf)

The detail file folder
https://drive.google.com/drive/folders/1Z-ACsJZp1kQs0VzaHMHi2R6-ipInSnWG?usp=sharing

Parents Reply
  • Thanks ketiljo. It work like a charm.

    I just replace the C3 and C4 with 20 pF cap ( CL = [20 pF+ 4 pF] / 2 = 12 pF, near the required 12.5 pF of  TXC 32.768kHz Crystal)

    And I replace C1 and C2 with 30 pF cap ( CL = [30 pF+ 4 pF] / 2 = 17 pF, near the required 18 pF of  QANTEK 32MHz Crystal) but exceed the  CL_HFXO  maximum 12 pF NRF52832.

    Finally, it can be connected by all my phones. I guess the root cause is the incorrect load caps that pull the crystal frequency.

    I will replace 32 MHz with another CL 8 pF crystal to meet the spec of NRF52832.

    Thanks a lot.

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