Can't connect anymore

[raffaeler]

Version 2.40
Supported engine: nRF Connect ^3.4.0
Current engine: 3.4.1

I recently upgraded the application. Since then, I cannot connect anymore to a JDY-10 bluetooth module. This module is just a bluetooth serial module bridge with a very limited configuration.

The Mobile app BLE Scanner can correctly connect and exchange data with the device, therefore I excluded problems on the module itself.

The steps I do from the Windows 10 PC are:

• unplug + plug the bt module and the nRF USB key
• start nRF Connect and select the nRF USB key to use as adapter
• start scan
• push the Connect button
  nRF Connect immediately answer with "Error - Device disconnected".

Log:

2020-06-20T09:45:34.598Z INFO Connecting to device
2020-06-20T09:45:34.601Z DEBUG      573 ->  [00 8c 01 00 93 3c 03 38 c1 a4 01 01 a0 00 50 00 14 00 01 06 00 06 00 00 00 90 01 01 ] type:     VENDOR_SPECIFIC reliable:yes seq#:6 ack#:6 payload_length:1c data_integrity:1 header_checksum:3b err_code:0x0
2020-06-20T09:45:34.628Z DEBUG   570/ 0 <-  [N/A] type:                 ACK reliable: no seq#:0 ack#:7 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.628Z DEBUG   571/ 0 <-  [01 8c 00 00 00 00 ] type:     VENDOR_SPECIFIC reliable:yes seq#:6 ack#:7 payload_length:6 data_integrity:1 header_checksum:94 err_code:0x0
2020-06-20T09:45:34.628Z DEBUG      574 ->  [N/A] type:                 ACK reliable: no seq#:0 ack#:7 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.856Z DEBUG   572/ 0 <-  [02 10 00 00 00 00 93 3c 03 38 c1 a4 02 06 00 06 00 00 00 90 01 ] type:     VENDOR_SPECIFIC reliable:yes seq#:7 ack#:7 payload_length:15 data_integrity:1 header_checksum:a2 err_code:0x0
2020-06-20T09:45:34.856Z DEBUG      575 ->  [N/A] type:                 ACK reliable: no seq#:0 ack#:0 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.856Z DEBUG GAP_EVT_CONNECTED time:2020-06-20T09:45:34.856Z connHandle:0 peerAddr:[address:A4:C1:38:03:3C:93 type:public addrIdPeer:0] role:central connParams:[minConnInterval:7_5 maxConnInterval:7_5 slaveLatency:0 connSupTimeout:4000]
2020-06-20T09:45:34.858Z INFO Connected to device A4:C1:38:03:3C:93
2020-06-20T09:45:34.866Z DEBUG      576 ->  [00 94 00 00 01 00 00 ] type:     VENDOR_SPECIFIC reliable:yes seq#:7 ack#:0 payload_length:7 data_integrity:1 header_checksum:bb err_code:0x0
2020-06-20T09:45:34.887Z DEBUG   573/ 0 <-  [N/A] type:                 ACK reliable: no seq#:0 ack#:0 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.887Z DEBUG   574/ 0 <-  [01 94 00 00 00 00 ] type:     VENDOR_SPECIFIC reliable:yes seq#:0 ack#:0 payload_length:6 data_integrity:1 header_checksum:d2 err_code:0x0
2020-06-20T09:45:34.887Z DEBUG      577 ->  [N/A] type:                 ACK reliable: no seq#:0 ack#:1 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.902Z DEBUG   575/ 0 <-  [02 11 00 00 00 3e ] type:     VENDOR_SPECIFIC reliable:yes seq#:1 ack#:0 payload_length:6 data_integrity:1 header_checksum:d1 err_code:0x0
2020-06-20T09:45:34.902Z DEBUG      578 ->  [N/A] type:                 ACK reliable: no seq#:0 ack#:2 payload_length:0 data_integrity:0 err_code:0x0
2020-06-20T09:45:34.902Z DEBUG GAP_EVT_DISCONNECTED time:2020-06-20T09:45:34.902Z connHandle:0 reason:62 reasonName:connFailedToBeEstablished
2020-06-20T09:45:34.902Z INFO Disconnected from device A4:C1:38:03:3C:93, reason: BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED

HTH

[bihanssen]

@raffaeler,
the error message you are getting is coming from the SoftDevice, meaning the bluetooth stack implementation running on the nRF device. It's not clear exactly what is causing the error message, it's often due to timing. You could try with different connection parameters (connection interval), or a different device, like a nRF development kit. A bluetooth sniffer trace could also provide more info.

What device are you using as adapter from nRF Connect for Desktop, is it the nRF52840 Dongle?

[raffaeler]

@bihanssen yes, I am using the nRF dongle.
I was wondering whether the recent software+firmware upgrade could be the cause. I never had problem before the upgrade.

Frankly I would exclude the timeout issue as I can instantaneously connect from Android / BLE Scanner without problems (and this was the case before the recent update).

[bihanssen]

@raffaeler, yes, the recent update is most likely part of the change in behavior. The firmware made a switch from SoftDevice v3 to SoftDevice v5 on the device, which may cause slight differences in behavior and timing. The fact that it still works on Android does not exclude timing issues in the combination of the nRF52840 SDv5 and your device.

[raffaeler]

Got it @bihanssen ... if the firmware is likely the issue, what should I do now? Downgrade? How?
Thanks

[bihanssen]

Best would be to find a way to make it work with the current version. As suggested, you could try different connection parameters, different nrf kits, or provide a sniffer trace for investigation (post on devzone for assistance).

If all else fails you could try to use an older launcher and using the previous BLE app version v2.3.2, though I wouldn't recommend it as that means losing out on updates.

[raffaeler]

That is the only nRF kit I have, sorry. This is a community project and that is a personal investment.
Could you please give me the devzone link? I believed this was the most appropriate way to give feedback.

BTW the devices I am using are merely rs232 adapters. They have very few settings (about 10) and, as I said, they works very well with either Arduino of from Android apps.

[bihanssen]

The devzone support portal is located at devzone.nordicsemi.com. Troubleshooting the issue is hard as we don't have your type of device and so can't reproduce. A sniffer trace or some other mean to reproduce would be needed for more investigation.