nRF connect for mobile on Android unable to discover nRF52840

[SubhanRVL]

Hi All,

I hope this message finds you well. I am reaching out to report an issue with my custom board design utilizing the nRF52840, programmed with the Nordic UART Service example.

The board can be successfully discovered through the nRF Connect for Desktop using the nRF52840 dongle as a central device. However, when tried with the nRF Connect for Mobile application on Android, the application is unable to discover the board.

Attached, please find the below screenshot showing the nRF52 dongle making a successful connection with the board.

I have experimented with various settings combinations on the nRF Connect for Mobile application, but none have proven effective in resolving the issue.

Your insights and assistance would be highly appreciated. If anyone has encountered a similar problem or has suggestions for troubleshooting, please share your experiences.

Thank you in advance for your support.

Regards,

Subhan

[Joakim Jakobsen]

Hi. 

That sounds strange. 

custom board design utilizing the nRF52840, programmed with the Nordic UART Service example.

Have you tested with other boards, i.e the nRF52840-DK? Do you see the same behavior there?

Which version of the SDK are you working with?

However, when tried with the nRF Connect for Mobile application on Android

Could you also add phone model and OS version?

_______________

Have you made sure that the device is disconnected from the dongle and nRF Connect for desktop - BLE app before you tried connecting to your smartphone?

Br, 
Joakim

[SubhanRVL]

Any update on this, please?

[Peter Hall]

Hi Jaakim, 

ok but to be clear it's any phone (Apple and Android) and some laptops that do not work.   The design has not been reviewed by you.   Can you provide a way for these to by uploaded for checking?

Could we have a call to discuss please? 

[Joakim Jakobsen]

Yes, that was my understanding. That no phone is able to discover the device.

Could you confirm that the sample running on your custom board it the peripheral UART sample? And that is an unmodified version of the sample?

Br,
Joakim

[SubhanRVL]

Hi,

Yes. It is the peripheral UART sample based on nRF Connect SDK v2.5.0.

It is modified to use an external crystal. I have enabled the following configuration settings:

• CONFIG_CLOCK_CONTROL_NRF_K32SRC_SYNTH=y

Also, the BLE name is changed to match our board. 

Regards,

Subhan

[Peter Hall]

Hi Jaakim,  do you have anything else we can look at?

[Peter Hall]

Hi Jaakim,  we are completely stuck on this.  The product that uses this chip is already established in the market and the BLE functionality is a product upgrade.   We will use 6-8K Nordic chips a year and at the moment if we can't get assistance from someone we will have to drop Nordic entirely and go with a different solution.  Please can you escalate this request for support.

[Peter Hall]

Hi Jaakim,  there is one more important point,   we do not fit the 32.768K LF Oscillator (market as optional on the schematics).   Could this cause any issues?  

[Peter Hall]

We have found the issue,   it was a poorly matched 32MHz Crystal.

devzone.nordicsemi.com/.../can-t-discover-nrf52832

[Joakim Jakobsen]

Hi. 

Apologize that I was not able to assist the last couple of days. I was out of office, and unable to answer. 

I'm glad you were able to figure it out. And thanks for sharing the solution. 

Closing the ticket, but you are welcome to post a new ticket if you have any more questions in the future. 

Br, 
Joakim