EFM32WG332 Datasheet, PDF (5/76 Pages) Silicon Laboratories – Operation from backup battery when main power drains out

...the world's most energy friendly microcontrollers
Descriptor-Based Scatter/Garther DMA and supports up to 6 OUT endpoints and 6 IN endpoints, in
addition to endpoint 0. The on-chip PHY includes all OTG features, except for the voltage booster for
supplying 5V to VBUS when operating as host.
2.1.11 Inter-Integrated Circuit Interface (I2C)
The I²C module provides an interface between the MCU and a serial I²C-bus. It is capable of acting as
both a master and a slave, and supports multi-master buses. Both standard-mode, fast-mode and fast-
mode plus speeds are supported, allowing transmission rates all the way from 10 kbit/s up to 1 Mbit/s.
Slave arbitration and timeouts are also provided to allow implementation of an SMBus compliant system.
The interface provided to software by the I²C module, allows both fine-grained control of the transmission
process and close to automatic transfers. Automatic recognition of slave addresses is provided in all
energy modes.
2.1.12 Universal Synchronous/Asynchronous Receiver/Transmitter (US-
ART)
The Universal Synchronous Asynchronous serial Receiver and Transmitter (USART) is a very flexible
serial I/O module. It supports full duplex asynchronous UART communication as well as RS-485, SPI,
MicroWire and 3-wire. It can also interface with ISO7816 SmartCards, IrDA and I2S devices.
2.1.13 Pre-Programmed USB/UART Bootloader
The bootloader presented in application note AN0042 is pre-programmed in the device at factory. The
bootloader enables users to program the EFM32 through a UART or a USB CDC class virtual UART
without the need for a debugger. The autobaud feature, interface and commands are described further
in the application note.
2.1.14 Low Energy Universal Asynchronous Receiver/Transmitter
(LEUART)
The unique LEUART^TM, the Low Energy UART, is a UART that allows two-way UART communication on
a strict power budget. Only a 32.768 kHz clock is needed to allow UART communication up to 9600 baud/
s. The LEUART includes all necessary hardware support to make asynchronous serial communication
possible with minimum of software intervention and energy consumption.
2.1.15 Timer/Counter (TIMER)
The 16-bit general purpose Timer has 3 compare/capture channels for input capture and compare/Pulse-
Width Modulation (PWM) output. TIMER0 also includes a Dead-Time Insertion module suitable for motor
control applications.
2.1.16 Real Time Counter (RTC)
The Real Time Counter (RTC) contains a 24-bit counter and is clocked either by a 32.768 kHz crystal
oscillator, or a 32.768 kHz RC oscillator. In addition to energy modes EM0 and EM1, the RTC is also
available in EM2. This makes it ideal for keeping track of time since the RTC is enabled in EM2 where
most of the device is powered down.
2.1.17 Backup Real Time Counter (BURTC)
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 or a 1 kHz ULFRCO. The BURTC is available in all Energy
Modes and it can also run in backup mode, making it operational even if the main power should drain out.
2014-06-13 - EFM32WG332FXX - d0191_Rev1.40
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