BLE 4.2 just works pairing with a 4.0 peripheral?

[keith v]

I'm trying to pair a Nordic SDK15 central to a non Nordic peripheral ( BLE 4.0)

I have no IO for passkeys

I'm testing by pairing Master control panel ( is it BLE 4.2?? ) to the peripheral. I get as far as the pairing confirmations, the master works, the slave fails.

shouldn't 4.2 be backwards compatible with 4.0?

Thanks

Keith Vasilakes

confirm failed.pcapng

[haakonsh]

Hey Keith,

I can't decode the sniffer log. Are you using the latest sniffer, v2?

You connection starts of as 4.0 then the connected device will negotiate optional 4.2/5.0 features. 

Do you have any debug information from the devices themselves?

Cheers,

Håkon.

[keith v]

That cap was from the old sniffer, here is a V2 one ( I didn't know there was a new sniffer ! :) New log attached

The central is master control panel, log attached also

The advertiser doesn't have a lot of debugging available, but I do know it gets a 'confirm value failed error' when checking the pairing status.

My main question is, why is the confirm still happening? it seems like it should be using legacy pairing/bonding.

(BTW I have a custom product that has the same behavior)

Thanks

Keith Vasilakes

7416.log.txtWS2 confirm failed.pcapng

[haakonsh]

Hey Keith,

It seems like you are attempting to use LE Secure Connection to pair. This is feature is not present in 4.0. You need to use Legacy pairing to be backwards compatible.  

Cheers,

Håkon.

[yes]

If roles were vice versa i.e. peripheral device shall be based on nordic nRF52832 / nRF52840 (configured to LE secure connection) and pairing master control panel support only BLE 4.0 , does the connection shall fail?  

[haakonsh]

If the device initiating the pairing process request LE secure connection and the other device only supports Legacy pairing then it will fail. 

If the device initiating the pairing request Legacy pairing and the other device support legacy pairing then it will succeed.