Differences in communication using nRF Connect for Mobile and for Desktop

[Hamilton Woods]

I am working with a company who is developing a product with BLE capability. The product has a BL653 Laird module which has Nordic nrf52833 chip. My job is to add BLE communication to our test suite to test the new product. BLE is not my forte. So far, I am able to communicate with the BLE chip in the product using nRF Desktop for Mobile version 4.26.0. I am able to scan for devices, connect to the BLE chip, pair with it, discover the services, list the characteristics for each of the services, and read and write values to the characteristics.

When I try to communicate with the BLE chip using a Nordic Semiconductor nRF52840 dongle and nRF Connect for Desktop version 4.0.4 on a Windows 10 Pro 64-bit computer, I can scan for devices, connect to the BLE chip, discover the services, and list the characteristics for each of the services. I am able to read values of the characteristics of some of the services, but not all. The characteristics of the services that I need to read and write appear to be encrypted. I think that means that I have to pair with the device.

nRF Connect for Desktop has several options for pairing: IO capabilities, Authentication, Keypress notifications, and Bonding. I have not found a combination of selections that allows me to pair with the device. When I attempt to read a value from a characteristic, the error, ATTERR_INSUF_ENCRYPTION (0x010F) is returned.

I am beginning to ask myself what is different between nRF Connect for Mobile and nRF Connect for Desktop that produces the differences in reading and writing values that I am experiencing.

Can anyone shed some light or help point me in a useful direction?

[Sigurd]

Hi,

nRF Connect for Desktop has several options for pairing: IO capabilities, Authentication, Keypress notifications, and Bonding. I have not found a combination of selections that allows me to pair with the device. When I attempt to read a value from a characteristic, the error, ATTERR_INSUF_ENCRYPTION (0x010F) is returned.

Looks like you need to encrypt the link. We have a guide on how to do this with nRF Connect Desktop BLE app here: https://infocenter.nordicsemi.com/topic/ug_nrfconnect_ble/UG/nRF_Connect_BLE/nRF_Connect_Pairing_devices.html

[Hamilton Woods]

Thank you for your reply. Based on the guide you linked, I have walked through many combination of security parameter settings. Every time I try to pair with the peripheral, regardless of the security settings applied, I get the error message, "Authentication failed with status BLE_GAP_SEC_STATUS_UNSPECIFIED".

I am trying to understand what to do to have nRF Connect for Desktop BLE encryption operate like nRF Connect for Mobile. Can I interrogate the encryption settings that nRF Connect for Mobile is using and then apply those settings in nRF Connect for Desktop BLE? If so, how do I interrogate the encryption settings that nRF Connect for Mobile is using?

[Sigurd]

Hi,

You could e.g. use the nRF sniffer

https://www.nordicsemi.com/Products/Development-tools/nrf-sniffer-for-bluetooth-le

Catch a sniffer trace for the connection between the mobile app and the nRF52833, then between the desktop app and the nRF52833, and then compare the logs to find the difference.