Datasheet

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LPC3152_3154 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.
Preliminary data sheet Rev. 0.12 — 27 May 2010 47 of 88
NXP Semiconductors
LPC3152/3154
• Provides ‘Supply_OK’ detection connected to the system reset signal.
7.6 Real-Time Clock (RTC)
The Real-Time Clock module keeps track of the actual date and time, also when the
system is switched off. Advanced Digital Rights Management (DRM) schemes require a
secure and accurate real-time clock for managing rights such as time-limited playback
rights.
This module has the following features:
• Normal power supply directly from Li-ion battery (PSU is by-passed).
• Backup power supply from (external) capacitor.
• Automatic switching between normal power supply and backup power supply.
• Signals power loss to indicate invalid real time clock readings.
• Runs on a 32 kHz oscillator.
• Ultra-low power consumption.
• The clock is implemented as a 32-bit counter at the rate of 1 Hz (derived from the 32
kHz clock).
• Alarm timer that can generate an interrupt. This interrupt is available both as an
internal signal as well as a signal on an external pin.
• The external interrupt (RTC_INT) can be used to switch on the system by switching
on the PSU through the PSU_PLAY pin.
• The internal interrupt signal can be used to wake-up the system from suspend mode
through the event router.
• Dedicated permanent supply domain.