Android application development

[Prithwi Chanda]

Hi,

We are developing an android application using nRF51422 to connect the BLE device, discovering characteristics and sending commands to the device. Here we are facing following difficulties.

1. Sometimes the nordic board is refusing to connect with the android phone.

2.  While testing with the application board is getting disconnected most often.

3. Sometimes the device gets reset and causing disconnection.

So we are looking for solutions for connection stability.

Thank you.

[awneil]

So what debugging have you done to find what's going on ?

https://www.argenox.com/library/bluetooth-low-energy/ultimate-guide-to-debugging-bluetooth-smart-ble-products/

https://infocenter.nordicsemi.com/topic/ug_gsg_ses/UG/gsg/debug.html

https://infocenter.nordicsemi.com/topic/ug_gsg_keil/UG/gsg/debug.html

www.avrfreaks.net/.../2418156

Prithwi Chanda said:

the nordic board is refusing to connect

How do you know it's specifically the Nordic board?

[Prithwi Chanda]

Hi,

I have done debugging using wireshark. there I faced the following issue.

When phone is sending LL_FEATURE_REQ packet it expects LL_FETURE_RES in return from the board like this

But when the nRF board is refusing to response LL_FETURE_RES device is not getting connected with phone like this

[Sigurd]

What SDK version and SoftDevice version are you using?

What phone model and brand are using ?

Do you see the same issue when using nRF-Connect for mobile ?

Please upload the wireshark log

[Prithwi Chanda]

1. SDK version:- 11 SoftDevice version:- 130

2. I have used Redmi Note 6 pro(Android 9), Moto G4 plus(Android 7), Samsung A107F(Android 9)

3. Yes I have faced same issue in nRF-Connect for mobile too

4. Wireshark log is attached bellow.

report7.pcapng

[Prithwi Chanda]

Right now I have found one more issue like, 

-  Once devices are connected it is expected to send Empty PDU to both sides.

- Some time slave is not sending Empty PDU and causing disconnection.

In bellow image, we can see the highlighted area and wireshark logs also attached

report13.pcapng

[Prithwi Chanda]

Hi, is there any update?

[Sigurd]

In the log report7.pcapng, we see the master/phone sends an LL_TERMINATE_IND packet. It’s not clear from the log why the master terminates the connection. If you use nRF-Connect for mobile app, the log there might reveal more information about why the phone disconnected.

In report13.pcapng, it seems like the slave suddenly stopped responding. This could happen if e.g. the device lost power, or if there was an assert in the code. You will likely need to do some debugging to find the root cause here. If you enable logging in the code, then nrf_log outputted over UART or Segger RTT, could provide you with some clues about what happened.

[Prithwi Chanda]

Master is sending LL_TERMINATE_IND packet when disconnection is done intentionally using the disconnect button. I m not worried about that. I am worried about when it stops responding suddenly. That is the reason why it is not connecting or suddenly getting disconnected.

[Sigurd]

Prithwi Chanda said:

I am worried about when it stops responding suddenly. That is the reason why it is not connecting or suddenly getting disconnected.

As mentioned, this could happen if e.g. the device lost power, or if there was an assert in the code. You will likely need to do some debugging to find the root cause . Maybe some error-code was returned somewhere ? Take a look at e.g. this post https://devzone.nordicsemi.com/f/nordic-q-a/10729/my-device-is-freezing-and-restarting