Datasheet

SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
242
14. Real-time Clock (RTC)
14.1 Description
The Real-time Clock (RTC) peripheral is designed for very low power consumption.
It combines a complete time-of-day clock with alarm and a two-hundred-year Gregorian calendar, complemented
by a programmable periodic interrupt. The alarm and calendar registers are accessed by a 32-bit data bus.
The time and calendar values are coded in binary-coded decimal (BCD) format. The time format can be 24-hour
mode or 12-hour mode with an AM/PM indicator.
Updating time and calendar fields and configuring the alarm fields are performed by a parallel capture on the 32-bit
data bus. An entry control is performed to avoid loading registers with incompatible BCD format data or with an
incompatible date according to the current month/year/century.
14.2 Embedded Characteristics
 Low Power Consumption
 Full Asynchronous Design
 Two Hundred Year Gregorian Calendar
 Programmable Periodic Interrupt
 Time, Date and Alarm 32-bit Parallel Load
 Write Protected Registers
14.3 Block Diagram
Figure 14-1. RTC Block Diagram
14.4 Product Dependencies
14.4.1 Power Management
The Real-time Clock is continuously clocked at 32768 Hz. The Power Management Controller has no effect on
RTC behavior.
14.4.2 Interrupt
RTC interrupt line is connected on one of the internal sources of the interrupt controller. RTC interrupt requires the
interrupt controller to be programmed first.
Bus Interface
32768 Divider TimeSlow Clock: SLCK
Bus Interface
Date
RTC Interrupt
Entry
Control
Interrupt
Control