Accuracy BLE: advertising

[pascal defesche]

Hello,

Is it possible to increase the accuracy of the advertise interval? Im attaching an oscilloscope screenshot showing the S110 device advertising with a 20ms interval and running on the internal LFCLK. Im toggling a pin on a radio notification, so when active and not active. As you can see the first interval is 26ms and the second is 22ms.

1. With an external LFCLK will this interval be more accurate and constant at 20ms?

Regards, Pascal

[Stefan Birnir Sverrisson]

Hi Pascal

This is actually a part of the BLE protocol. You set the advertising interval to 20 milliseconds, the softdevice will automatically add few milliseconds to the advertising interval. The number of added milliseconds is randomly picked. The purpose is to prevent that a scanning device with the same scanning interval will never discover the peripheral device.

[pascal defesche]

Thanks for your explanation!