Real Time Clock (Rtc); Overview; Features - Nuvoton ARM Cortex NuMicro M451 Series Technical Reference Manual

6.12

Real Time Clock (RTC)

6.12.1 Overview

The Real Time Clock (RTC) controller provides the real time and calendar message. The RTC
offers programmable time tick and alarm match interrupts. The data format of time and calendar
messages are expressed in BCD format. A digital frequency compensation feature is available to
compensate external crystal oscillator frequency accuracy.
The RTC controller also offers 80 bytes spare registers to store user's important information. The
spare registers content is cleared when specified event on tamper pin is detected.

6.12.2 Features


Supports real time counter in RTC_TIME (hour, minute, second) and calendar counter in
RTC_CAL (year, month, day) for RTC time and calendar check

Supports alarm time (hour, minute, second) and calendar (year, month, day) settings in
RTC_TALM and RTC_CALM

Supports alarm time (hour, minute, second) and calendar (year, month, day) mask enable in
RTC_TAMSK and RTC_CAMSK

Selectable 12-hour or 24-hour time scale in RTC_CLKFMT register

Supports Leap Year indication in RTC_LEAPYEAR register

Supports Day of the Week counter in RTC_WEEKDAY register

Frequency of RTC clock source compensate by RTC_FREQADJ register

All time and calendar message expressed in BCD format

Supports periodic RTC Time Tick interrupt with 8 period interval options 1/128, 1/64, 1/32,
1/16, 1/8, 1/4, 1/2 and 1 second

Supports RTC Time Tick and Alarm Match interrupt

Supports chip wake-up from Idle or Power-down mode while a RTC interrupt signal is
generated

Supports 80 bytes spare registers and a snoop pin detection to clear the content of these
spare registers
May. 4, 2018 Page 557 of 1006
M451
Rev.2.08