External RTC (Square Wave Buffer or Full-time 32 kHz square wave)

[Arash-Spec]

Hello, I have decided to use an external RTC (M41T64) to wake up the nRF52832 from system OFF mode. I am also planning to use the RCT to generate generate the 32.768 kHz to feed into the nordic BLE module (nRF52832). 

The RTC module (M41T64) has two 32.768 kHz outputs: 

1. Programmable Square Wave Buffer 
2. Full-time 32.768 kHz Square Wave

I would like to know which source is best for power consumption and provides better CLK accuracy for the Nordic BLE module and also what are the differences between the two? 

Thanks in advance.

[Stian Røed Hafskjold]

Hi, I'm sorry but you will have to ask the manufacturer of the M41T64 about the differences between these two clock sources and their accuracy/current consumption.