EFM32WG Datasheet, PDF (105/834 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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10 EMU - Energy Management Unit
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10.1 Introduction
What?
Quick Facts
The EMU (Energy Management Unit)
handles the different low energy modes in the
EFM32WG microcontrollers.
Why?
The need for performance and peripheral
functions varies over time in most
applications. By efficiently scaling the
available resources in real-time to match
the demands of the application, the energy
consumption can be kept at a minimum.
How?
With a broad selection of energy modes,
a high number of low-energy peripherals
available even in EM2, and short wake-
up time (2 µs from EM2 and EM3),
applications can dynamically minimize energy
consumption during program execution.
The Energy Management Unit (EMU) manages all the low energy modes (EM) in EFM32WG
microcontrollers. Each energy mode manages if the CPU and the various peripherals are available. The
energy modes range from EM0 to EM4, where EM0, also called run mode, enables the CPU and all
peripherals. The lowest recoverable energy mode, EM3, disables the CPU and most peripherals while
maintaining wake-up and RAM functionality. EM4 disables everything except the POR, pin reset and
optionally Backup RTC, 512 byte data retention, GPIO state retention, and EM4 reset wakeup request.
The various energy modes differ in:
• Energy consumption
• CPU activity
• Reaction time
• Wake-up triggers
• Active peripherals
• Available clock sources
Low energy modes EM1 to EM4 are enabled through the application software. In EM1-EM3, a range
of wake-up triggers return the microcontroller back to EM0. EM4 can only return to EM0 by power on
reset, external pin reset, EM4 GPIO wakeup request, or Backup RTC interrupt.
10.2 Features
• Energy Mode control from software
• Flexible wakeup from low energy modes
• Low wakeup time
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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