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17.1 Features
17.2 Description
The Real Time Clock (RTC) is a set of counters for measuring time when system power is
on and optionally when it is off. It uses little power in Power-down mode. On the
LPC2101/02/03, the RTC can be clocked by a separate 32.768 KHz oscillator or by a
programmable prescale divider based on the APB clock. Also, the RTC is powered by its
own power supply pin, VBAT, which can be connected to a battery or to the same 3.3 V
supply used by the rest of the device.
17.3 Architecture
User manual
UM10161
Chapter 17: Real Time Clock
Rev. 01 — 12 January 2006
•
Measures the passage of time to maintain a calendar and clock.
•
Ultra Low Power design supports battery powered systems.
•
Provides Seconds, Minutes, Hours, Day of Month, Month, Year, Day of Week, and Day
of Year.
•
Can be used with dedicated 32 kHz oscillator or programmable prescaler from APB
clock.
•
Dedicated power supply pin can be connected to a battery or to the main 3.3 V.
CLOCK GENERATOR
CLK1
CCLK
TIME COUNTERS
counter
enables
Fig 57. RTC block diagram
Rev. 01 — 12 January 2006
CLK32k
MUX
strobe
COMPARATORS
COUNTER INCREMENT
INTERRUPT ENABLE
INTERRUPT GENERATOR
User manual
RTC OSCILLATOR
REFERENCE CLOCK DIVIDER
(PRESCALER)
ALARM
REGISTERS
ALARM MASK
REGISTER
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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