No BLE discovery on Android 7.0 and above

[Ketan Vaghela]

I have compiled ble_app_blinky sample code from nRF5_SDK_17.0.2_d674dde SDK and loaded it with s132_nrf52_7.2.0_softdevice.hex in my nrf52382 board. I can discover this device on < Anrodid version 7.0  mobile only. But When I load sample hex file into Thingy52 then I was able to discover in my all phone. Can I know what will be wrong in my hardware ?

[JONATHAN LL]

Hi Ketan,

Can you share your hex file you used to test?

To clarify:
You have a custom PCB with nrf52832 and that is the one that only connects to Android 7 ?

If so can you share the Hardware files and schematic?

Regards,
Jonathan

[Ketan Vaghela]

s132_nrf52_7.2.0_softdevice.hex8461.nrf52832_xxaa.hex

Hi Jonathan,

My board (custom pcb) connects to mobile device having android version below 7.0, however if I put same .hex in Thingy52, it connects to all devices. Not sure if it is hardware issue or some settings in software.

Here are .hex files and schematic snippet of nrf52832 used in custom board. Please let me know if you need any additional details. Thanks!

[JONATHAN LL]

Hi Ketan,
I tested the hex on a nrf52832 DK and it works on Android 10, so I believe it to be a HW problem.

looking over your schematic a coupled of thing to note. 

If you are using a QFN package like the QFAA
DEC2 pin 32, should not be connected. Leave it open

DEC3 pin 33, should be 100pF.
Looks like you have 0.1uF,

DC/DC components.
L2 (10uH) and L3 (15nH) + DEC4-VSS Capacitor (1.0uF)
Looks like you have 15uH instead on L3 and 0.1uF on the Cap.


Can you confirm that the component values that you had in in the schematic is the ones you used. If that is the case then try to update the component values to the recommended ones and see if that fixes the problem.   Here is a link to the nrf52832 QFAA DC/DC regulator setup. 

Additional questions,
You have connected both of the crystal oscillators? 

Regards,
Jonathan

[Ketan Vaghela]

Hi Jonathan,

Thanks for your swift reply, I tried changing values of component as you described but unfortunately that did not help resolving the issue. Please let me know if I should check any other area(s).

On your question about crystal oscillator- yes, Y1 - 32kHz and Y3 - 32MHz, both connected on board.

[JONATHAN LL]

Hi Ketan,

How many devices have you tested with? 

What devices where they? tablets, phones and pc?

Are you using the nrf connect app on the mobile devices?


To clarify:
Are you able to discover the the device and connect on android 7.   

Regards,
Jonathan

[Ketan Vaghela]

Hi Jonathan,

Sorry, it took long time. So far I was relying on words of different testing person (as per their inputs they checked on some older android phones having android version below 7 and it was working there, but when they tried on newer phones with recent android version, they were not able to discover the device). But when I checked myself, I figured some weird results.

When I checked myself, on four android phones:

1. Redmi K20 Pro: Android 10, Bluetooth 5.0 -- able to discover device

2. Vivo V11 Pro: Android 9, Bluetooth 5.0 -- able to discover device

3. Samsung Galaxy M21: Android 10, Bluetooth 5.0 -- NOT able to discover device

4. Oppo F7: Android 8, Bluetooth 4.2 - NOT able to discover device

So, first of all, sorry for asking question without verifying the details myself. it looks like, it is not related to Android version or Bluetooth Radio version, it is something else. It is most likely that it is hardware design issue (as when I put same .hex on Thingy52 I've, it can be discovered by all devices), but sadly, could not figure out where things are wrong. Thanks once again for your time.

[JONATHAN LL]

Hi,

Different  cheep phones/tablets or other electronics can have varying results when it comes to working correctly with devices. Not all hardware is held to the same standards for the specifications making compatibility difficult especially on cheaper or of brand components/products. 

If you want you can submit a hardware review of you device, share your schematics and we can give some feedback on possible improvements. 

Regards,
Jonathan

[Ketan Vaghela]

Hi Jonathan,

OK, thanks! For hardware review- do you need hardware/board + schematic? Or just schematic?

[JONATHAN LL]

Hi,

Both is best as we can then see if there is anything related to layout that could cause a potential problem. 

If you don't want to share your hardware files publicly you can crate a new private Devzone ticket and add the files there. 

If you could provide the schematic as a pdf and the hardware layout files in Gerber format then that would be great. Alternatively if you have Altium project file that you can zipp and attach the files that will also work.


Regards,
Jonathan