at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 165

• Manufacturer Part Number: at91rm3400
• Description: Atmel Advanced At91 Arm Microcontroller
• Manufacturer: ATMEL Corporation

Real Time Clock (RTC)
Overview
Block Diagram
Figure 52. RTC Block Diagram
Product
Dependencies
Power
Management
Interrupt
1790A–ATARM–11/03
Crystal Oscillator: SLCK
Bus Interface
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 calen-
dar, 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 for-
mat 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.
Important features of the RTC include:
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The Real-time Clock is continuously clocked at 32768 Hz. The Power Management Controller
has no effect on RTC behavior.
The RTC Interrupt is connected to interrupt source 1 (IRQ1) of the advanced interrupt control-
ler. This interrupt line is due to the OR-wiring of the system peripheral interrupt lines (System
Timer, Real Time Clock, Power Management Controller, Memory Controller, etc.). When a
Low Power Consumption
Full Asynchronous Design
Two Hundred Year Calendar
Programmable Periodic Interrupt
Alarm and Update Parallel Load
Control of Alarm and Update Time/Calendar Data In
32768 Divider
Bus Interface
Control
Entry
Time
Interrupt
Control
Date
AT91RM3400
RTC Interrupt
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