nrf52dk connection fails for central sample

[Mark G.]

Hi all,

I am currently testing on nrf52dk (PCA10040, 3.0.0) with NCS v3.3. Note: I also tested with vanilla Zephyr and see the same issue.

The code I run is to 100% the central sample from: "samples/bluetooth/central" with default nrf52dk/nrf52832 board setting.

with the following proj.conf:

CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_MODE_DEFERRED=y
CONFIG_LOG=y

CONFIG_BT=y
CONFIG_BT_CENTRAL=y

I have the issue that some connection attempts get closed immediately:

Connected: CC:6B:3E:7F:02:B8 (random)
[00:00:04.350,341] <wrn> bt_conn: conn 0x20001c98 failed to establish. RF noise?
Disconnected: CC:6B:3E:7F:02:B8 (random), reason 0x3e

I have multiple peripheral devices that I need to connect to. Some devices work perfectly, some specific ones fail all the time with the error above. It seems these device behave a little different then others. What would be the proper way to investigate these issues and how could we make the connection more robust?

[Simonr]

Hi

What are these peripheral devices exactly? Are they custom boards or also nRF52 DKs or similar? Do you see these disconnections once multiple devices are already connected or does it only occur on specifc peripherals?

The "0x3e" disconnect reason points to the other end (peripheral device) triggered the disconnect, so do you have logging enabled on the peripheral device to get more information on these disconnects as well?

Best regards,

Simon

[Mark G.]

The peripherals are devices on the market, not from us. I also dont know which MCU or Tech stack they use. We cannot see any logs from this device. All I know is that these peripherals work perfectly together with other central devices. 

In my logs on central side I also see the following strange behavior. I step into the Service Discovery but i imminently see in the first service discover callback that: const bt_gatt_attr* attr. is already NULL. I think its because the connection maybe fails / gets closed even before I can properly do the service discovery.