nRF8001 connection interval

[PhilippS]

Hello!

I am trying to change the connection interval of the nRF8001 (connected to the PCA10000 usb dongle). Changing from 7.5ms to 1sec is very fast, but changing it back from 1sec to 7.5ms takes 10-30seconds. The MasterControlPanel shows the right connection parameters but it takes so long. Is there a way to change it faster from 1sec to 7.5ms?

Thank you!

[David Edwin]

Are you changing the connection interval from the master control panel or from the nRF8001 ?

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If you are changing from Master control panel, you should get whatever connection interval you want and it will be applied fairly quickly.

If you are changing from the nRF8001 the GAP Connection Update Parameter procedure in the Bluetooth specification will be a choke point, as it would not allow changes faster than 30 seconds between changes from the peripheral side.

I also see there is an additional delay for the ACI Change timing request that is set by default to 5 seconds in the nRFgo studio settings for the nRF8001 ( nRF8001 configuration > GAP settings tab > Delay for ACI Change Timing Request ). 

Does this answer your question ?

[awneil]

ISTR this has been discussed before?

There is (or may be) a minimum interval between connection parameter updates - some systems may not support/allow it at all ?

EDIT

Also, there is no guarantee that a Host will actually accept the requested connection interval - in particular, phones/tablets may not accept requests for very short intervals ...

[PhilippS]

I changed it from the nRF8001.

I read about the same problem in this discussion:

https://devzone.nordicsemi.com/f/nordic-q-a/4289/nrf8001-and-changetimingraequest-30-second-delay

Yes, thank you very much for your complete answer. It is clear to me now.

[PhilippS]

Thanks for your reply!

I had the problem that my phone didn't support a lower connection intervals but i used the PCA10000 and it supports low connection intervals.