[BLE Central] Failed to exchange gatt MTU: err 0x0e

[Martdur]

Hello Nordic Team, 

I'm developing a BLE multilink central device, I've managed to connect and subscibe to differents devices but I have some troubles connecting and subscribing to one particular BLE sensor.

I'm working with two cycling power pedals from the same brand (One right one left), I managed to subscribe to the power characteristics of the left sensor, but I get error while exchanging the MTU with the right pedals(err 0x0e).

I'm using nordic connect sdk v2.2.0 with zephyr on custom board.

My config: 

Here is the log from the nrf53840 : 

Here the wireshark traces for both right and left pedals:

4341.FailedExaktRightt.pcapng

0131.SucceedExaktLeft.pcapng

I made some tests with my phone on the right pedals and everything was ok, here is the trace: 

3364.SucceedExaktRighPhonet.pcapng

I've tried other config like:

CONFIG_BT_AUTO_PHY_UPDATE=y

CONFIG_BT_GATT_AUTO_UPDATE_MTU=y

CONFIG_BT_AUTO_DATA_LEN_UPDATE=y

But this doesn't seems to help at all, making the connexion to both pedals fail.

Thanks in advance.

Martin

[Martdur]

Thanks for the information, we'll try to do futher search later in the development process.

I will keep you in touch.

Best regards.

Martin.

[Martdur]

Hello Kenneth and Tesk,

I've managed to connect and subscribe to both sensor now, just by reducing the connexion interval (7.5ms).

I see why it can help the exchange between devices, but not why we didn't see any response from the sensor on the last wireshark trace.

Thanks for the help.

Kinds regards.

Martin.