SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The real-time clock is a precise timer which can generate interrupts on intervals specified by the user. Interrupts can occur every second, minute, hour, or day. The clock can track the passage of real time for durations of several years, provided it has a sufficient power source the entire time.
The basic purpose of the RTC is to keep time of day. The other equally important purpose of the RTC is for Digital Rights management. Some degree of tamper proofing is needed to ensure that simply stopping, resetting, or corrupting the RTC does not go unnoticed so that if this occurs, the application can re-acquire the time of day from a trusted source. Another purpose of the RTC is to wake up the rest of the chip from a power-down state.
Alarms are available to interrupt the host processor at a particular time, or at periodic intervals, such as once per minute or once per day. In addition, the RTC can interrupt the CPU every time the calendar and time registers are updated, or at programmable periodic intervals.
Figure 23-1 shows the RTC functional block diagram.