14.2 Module Overview

The RTC module in the SAM devices is a 32-bit counter, with a 10-bit programmable prescaler. Typically, the RTC clock is run continuously, including in the device's low-power sleep modes, to track the current time and date information. The RTC can be used as a source to wake up the system at a scheduled time or periodically using the alarm functions.

In this driver, the RTC is operated in Count mode. This allows for an easy integration of an asynchronous counter into a user application, which is capable of operating while the device is in sleep mode.

Whilst operating in Count mode, the RTC features:
  • 16-bit counter mode

    • Selectable counter period

    • Up to six configurable compare values

  • 32-bit counter mode

    • Clear counter value on match

    • Up to four configurable compare values