EFM32WG Datasheet, PDF (565/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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22 BURTC - Backup Real Time Counter
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What?
Quick Facts
The Backup Real Time Counter (BURTC)
allows timekeeping in all energy modes.
Running on the LFXO, LFRCO, or ULFRCO,
the BURTC can run in EM4 with a total
current consumption less than 0.5uA. The
Backup RTC is also available when the
system is in backup mode.
Why?
Timekeeping over long time periods is
required in many applications, while using as
little power as possible.
How?
The 32-bit Backup RTC is available
in all energy modes and selectable
prescaling allows the system to stay in
low energy modes for long a time and
still maintain reliable timekeeping. The
BURTC also includes a feature allowing
seamless switching of clock frequency, while
maintaining resolution of the counter.
22.1 Introduction
The Backup Real Time Counter (BURTC) contains a 32-bit counter and is clocked either by a 32.768
kHz crystal oscillator, a 32.768 kHz RC oscillator, a 2kHz RC oscillator, or a 1kHz RC oscillator. A variety
of prescaler settings are also available for the 32.768 kHz oscillators. The Backup RTC is available in
all energy modes, making it ideal for time keeping with minimal energy consumption. The ability to keep
running while the system is in backup mode allows the Backup RTC to keep track of time, even if the
main power should drain out.
22.2 Features
• 32-bit Real Time Counter
• Prescaler for LFXO and LFRCO, 32.768 kHz/2^N, N = 0-7
• Available in all energy modes and backup mode.
• Timestamp and optionally switch to low power mode upon entry to backup mode.
• Oscillator failure detection.
• EM4 operation and wake-up.
• Not reset by system reset, only by software, pin reset, or power loss.
• Seamless frequency shifting while keeping track of time.
• 512 bytes of general purpose data retention.
• Detection of corrupt writes to retention registers when losing main power.
• PRS producer.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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