https://devzone.nordicsemi.com/f/nordic-q-a/18796/regarding-rtc-of-nrf51822Regarding the RTC prescaler of nRF51822, I found out that it is the following. Timer and RTC prescaler behavior by TASKS_CLEAR is different, When TASKS_CLEAR is executed at TIMER, the TIMER counter is cleared, The prescaler counter is not cleareden-USTelligent Community 13Thu, 05 Jan 2017 07:46:06 GMThttps://devzone.nordicsemi.com/thread/72596?ContentTypeID=1Thu, 05 Jan 2017 07:46:06 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8914c95d-8bde-4ae5-afbf-e24bfa3a91b4Shinya Sakaida<p>Dear RK</p> <p>Timer and RTC prescaler behavior by TASKS_CLEAR is different in real machine I am checking it, but how? I confirmed it by synchronizing the RTC between two nRF51822. Corresponding to the time until execution of TASKS_CLEAR after interrupt The two are out of synchronization.</p> <p>Best Regards Shinya Sakaida</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/72595?ContentTypeID=1Thu, 05 Jan 2017 06:42:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d87f8e6f-c0f6-4dfd-85d7-a31a1fff2cf6RK<p>That is just not correct. In neither the TIMER nor the RTC does the TASK_CLEAR affect the PRESCALER in any way, only the counter is cleared, the PRESCALER is left at same exact value you set it to. The only way to change the PRESCALER is to stop the RTC, write the register, and start it up again.</p> <p>If you are seeing different behaviour, you have a bug.</p><div style="clear:both;"></div>