If during an SMP session the Master attempts to re-encrypt the link, the encryption request reaches the 531 Host after an SMP timeout is generated
ID: LPCBARESDK-993
Status: Open
First reported: SDK6.0.14
Fixed in: TBD
Description
During an SMP session, the Master (usually the smartphone) issues a request to an encryption protected attribute. The Slave (DA14531) replies with an “Insuffienct Encryption” response, and this causes the Master to refresh the encryption (pause and restart it) right after Slave’s key transfer and before Master’s key transfer during Bonding.
The DA14531 Controller stalls and does not forward the new encryption request to its Host in time. The phone remains waiting in the new Encryption Procedure and unavoidably an SMP timeout occurs in DA14531. After the SMP timeout, the Encryption Request is forwarded to the DA14531 Host. The encryption may be succesfull afterwards, but the SMP session is lost (despite the Master transmitting its pending keys).
Other Link Layer procedures that require Host confirmation (parameter update) reach the DA14531 Host in time with no trouble.
Workaround
No workaround is known at this time. Please Contact your Renesas representative to obtain appropriate support.