Andrew Fernandes

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9 years, 11 months ago.

Minimum advertising interval?

Hello - I've been looking at the (very nice!) BLE_API for the nRF51822, and was wondering about the GAP advertising parameters.

In the headers and API documentation, the GAP_ADV_PARAMS_INTERVAL_MIN_NONCON is 0x0020, corresponding to 20 ms.

Is this limit enforced by the BLE library or the device firmware?

We require an 11.25 ms connection interval for some HID work we are doing (we've already checked that the central will accept it), so are hoping that the 20 ms minimum is advisory only.

Thank you!

Question relating to:

Last updated: 27 Aug 2020
The nRF51822-mKIT is a low cost ARM mbed enabled development board for Bluetooth® Smart designs with the nRF51822 SoC. The kit gives access to all GPIO pins via pin headers …

1 Answer

Runar Skjerve
9 years, 11 months ago.

Hi,

20ms is the minimum advertisement interval allowed by the Bluetooth specification.

The minimum connection interval is 7.5 ms so it should be well within your requirements as long as it is supported by the central device.

Best regards,

Ghhaaaa! "advertisement" interval versus "connection" interval... I'm constantly getting these mixed up in my head because certain API "how to" document (cough)Core(cough)Bluetooth mix them up, as do many people asking questions online (like me).

Thanks for the answer, and I appreciate you NOT saying "advertising interval is not the same as connection interval, you idiot!" :-)

Cheers, -Andrew.

posted by Andrew Fernandes 23 Apr 2014