0x3d ble error

[Sameer]

Dear All,

We are implementing 8 Pheripheral Nodes and one central node with S110 and S120 respectively. We have our custom board with us we are able to connect the pheripheral nodes and connection lies for some time half n hour and after that nodes gets disconnected and we get the 0x3d ERROR from pheripheral.

We are using SDK10 with pheripheral and Softdevice version is 8.0.0 and at central side we have SDK8 and softdevice version is 2.1.0.

Can anybody tell me what is the exact meaning of this error code?

[John]

According to the spec and the definition in ble_hci.h that is a MIC failure. It means a message failed a Message Integrity Check (MIC). The MIC is appended to a message payload on encrypted connections and is used to authenticate the packet. Apparently it is possible to pass the CRC check but fail the MIC check and this error is the result.

[Sameer]

Dear John,

Thanks alot for your reply.

We are not deleting the BOND table data in pheripheral nodes.Do we need to do it or not? What will be the cause of this error to come?

[John]

If you want your peripheral to remember its pairing with the central then you do not want to delete the bonding information in the peripheral. I do not know the cause of the error.

[Hung Bui]

Hi Sammer,

0x3d is BLE_HCI_CONN_TERMINATED_DUE_TO_MIC_FAILURE. Bad MIC is not common reason for disconnection. Actually, I haven't seen this disconnection reason before. This should only happen when the key used for encryption is wrong. But in your case, the 2 device worked for half an hour. Which is pretty strange.

Could you reproduce the issue with any example in the SDK so that we can try to do the same here ?

Could you let us know which hardware part you are using for testing , especially the chip revision (you can read the laser mark on top of the chip). I assume you are testing with 2 nRF51 chip connected to each other.