LPC1857_53 NXP Semiconductors, LPC1857_53 Datasheet - Page 78

• Manufacturer Part Number: LPC1857_53
• Description: The LPC1857/53 are ARM Cortex-M3 based microcontrollers for embedded applications
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC1857_53
Objective data sheet
7.18.2.1 Features
7.19.1.1 Features
7.19.2.1 Features
7.18.2 Digital-to-Analog Converter (DAC)
7.19.1 RTC
7.19.2 Event monitor/recorder
7.19 Peripherals in the RTC power domain
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 when the CPU does not access its
registers, especially in the reduced power modes. A separate 32 kHz oscillator clocks the
RTC. The oscillator produces a 1 Hz internal time reference and is powered by its own
power supply pin, VBAT.
The event monitor/recorder allows recording and creating a time stamp of events related
to the WAKEUP pins. Sensors report changes to the state of the WAKEUP pins, and the
event monitor/recorder stores records of such events. The event recorder can be
powered by the backup battery.
The event monitor/recorder can monitor the integrity of the device and record any
tampering events.
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10-bit resolution
Monotonic by design (resistor string architecture)
Controllable conversion speed
Low power consumption
Measures the passage of time to maintain a calendar and clock. Provides seconds,
minutes, hours, day of month, month, year, day of week, and day of year.
Ultra-low power design to support battery powered systems. Less than <tbd> required
for battery operation. Uses power from the CPU power supply when it is present.
Dedicated battery power supply pin.
RTC power supply is isolated from the rest of the chip.
Calibration counter allows adjustment to better than 1 sec/day with 1 sec resolution.
Periodic interrupts can be generated from increments of any field of the time registers.
Alarm interrupt can be generated for a specific date/time.
Supports three digital event inputs in the VBAT power domain.
An event is defined as a level change at the digital event inputs.
For each event channel, two timestamps mark the first and the last occurrence of an
event. Each channel also has a dedicated counter tracking the total number of events.
Timestamp values are taken from the RTC.
Runs in VBAT power domain, independent of system power supply. The
event/recorder/monitor can therefore operate in Deep power-down mode.
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 14 December 2011
32-bit ARM Cortex-M3 microcontroller
LPC1857/53
© NXP B.V. 2011. All rights reserved.
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