RE: nRF8001 and ChangeTimingRequest: 30 second delay

awneil — Fri, 13 Nov 2015 13:43:07 GMT

I've seen delays of 2 minutes or more!

It seems like the hosts (I'm using Android) just don't like this!

RE: nRF8001 and ChangeTimingRequest: 30 second delay

Garth Snyder — Tue, 04 Nov 2014 22:44:11 GMT

A thorough and complete answer, as always. What a strange protocol restriction, though....

RE: nRF8001 and ChangeTimingRequest: 30 second delay

David Edwin — Tue, 04 Nov 2014 14:15:01 GMT

The ChangeTimingRequest is tied to the L2CAP Connection Parameter Update request in the specification, that specifies that the timing change should not be requested more often than 30 seconds. In addition there are issues in iOS and Android (Samsung) when the Connection Parameter Update request is requested faster than 30 seconds. This is likely due to implementation issues on the respective operating systems.

"The Peripheral shall not send an L2CAP Connection Parameter Update Request command within TGAP(conn_param_timeout = 30 seconds) of an L2CAP Connection Parameter Update Response being received. When the Central accepts the Peripheral initiated Connection Parameter Update, the Central should initiate the Link Layer Connection Update procedure defined in [Vol. 6], Part B Section 5.1.1 with the required connection parameters within TGAP(conn_param_timeout = 30 seconds ). "

However in some cases when your required timing params are placed in the GAP Characteristic called Preferred Peripheral Connection Parameters, the peer device (Windows and maybe Android) will automatically connect at that connection parameter, this may help in mitigating the issue a bit.