Bluetooth Alarm Clock

Question

Hi, 
 I want to use nrf51 development board as a bluetooth alarm clock using internal RTC . How can I generate timestamps to determine current date and time. Can the timer library be used for this purpose?

Einar Thorsrud · Accepted Answer

You can use the RTC directly, or you can use the application timer library. You would probably want to make the timer timeout at a regular interval, such as once every second, and calculate the current time based on that. 
 Note that the accuracy your time depend on the 32 kHz clock source. If you use the internal RC and calibrate it every 4 seconds, the accuracy will be ±250 ppm. That means that the time can be off by as much as ±21.6 s per day, so it may not be accurate enough.

Bluetooth Alarm Clock

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