The relationship of external 32.769khz crystal and the stability of the BLE connection

[Tom.Fu]

Dear Support Team

For the nRF52805, If we use D5 and D6 as the GPIO and use internal 32.768khz, do this affect the stability of the BLE connection? Many thanks.

[Einar Thorsrud]

Hi,

The stability of BLE connections will not be affected provided that you configure the software correctly. The internal LFRC will have an accuracy of +-500 ppm when calibrated regularily, and so that must be properly configured. This is what is refered to as the Sleep Clock Accuracy (SCA) in Bluetooth, and there will be more slack to account for more clock drift. See this post for how to properly use the internal LFRC in the nRF Connect SDK.