Preliminary
...the world's most energy friendly microcontrollers
EFM32WG940 DATASHEET
F256/F128/F64
Preliminary
•
ARM Cortex-M4 CPU platform
• High Performance 32-bit processor @ up to 48 MHz
• DSP instruction support and floating-point unit
• Memory Protection Unit
•
Flexible Energy Management System
• 20 nA @ 3 V Shutoff Mode
• 0.4µA @ 3 V Shutoff Mode with RTC
• 0.65 µA @ 3 V Stop Mode, including Power-on Reset, Brown-out
Detector, RAM and CPU retention
• 0.95 µA @ 3 V Deep Sleep Mode, including RTC with 32.768 kHz
oscillator, Power-on Reset, Brown-out Detector, RAM and CPU
retention
• 67 µA/MHz @ 3 V Sleep Mode
• 230 µA/MHz @ 3 V Run Mode, with code executed from flash
•
256/128/64 KB Flash
•
32/32/32 KB RAM
•
52 General Purpose I/O pins
• Configurable push-pull, open-drain, pull-up/down, input filter, drive
strength
• Configurable peripheral I/O locations
• 16 asynchronous external interrupts
• Output state retention and wake-up from Shutoff Mode
•
12 Channel DMA Controller
•
12 Channel Peripheral Reflex System (PRS) for autonomous in-
ter-peripheral signaling
•
Hardware AES with 128/256-bit keys in 54/75 cycles
•
Timers/Counters
• 4× 16-bit Timer/Counter
• 4×3 Compare/Capture/PWM channels
• Dead-Time Insertion on TIMER0
• 16-bit Low Energy Timer
• 1× 24-bit Real-Time Counter and 1× 32-bit Real-Time Counter
• 3× 16/8-bit Pulse Counter
• Watchdog Timer with dedicated RC oscillator @ 50 nA
•
Integrated LCD Controller for up to 8×18 segments
• Voltage boost, adjustable contrast and autonomous animation
•
Backup Power Domain
• RTC and retention registers in a separate power domain, avail-
able in all energy modes
• Operation from backup battery when main power drains out
•
Communication interfaces
• 3× Universal Synchronous/Asynchronous Receiv-
er/Transmitter
• UART/SPI/SmartCard (ISO 7816)/IrDA/I2S
• 2× Low Energy UART
• Autonomous operation with DMA in Deep Sleep
Mode
2
• 2× I C Interface with SMBus support
• Address recognition in Stop Mode
• Universal Serial Bus (USB) with Host & OTG support
• Fully USB 2.0 compliant
• On-chip PHY and embedded 5V to 3.3V regulator
•
Ultra low power precision analog peripherals
• 12-bit 1 Msamples/s Analog to Digital Converter
• 8 single ended channels/4 differential channels
• On-chip temperature sensor
• 12-bit 500 ksamples/s Digital to Analog Converter
• 2× Analog Comparator
• Capacitive sensing with up to 16 inputs
• 3× Operational Amplifier
• 6.1 MHz GBW, Rail-to-rail, Programmable Gain
• Supply Voltage Comparator
•
Low Energy Sensor Interface (LESENSE)
• Autonomous sensor monitoring in Deep Sleep Mode
• Wide range of sensors supported, including LC sen-
sors and capacitive buttons
•
Ultra efficient Power-on Reset and Brown-Out Detec-
tor
•
Debug Interface
• 2-pin Serial Wire Debug interface
• 1-pin Serial Wire Viewer
• Embedded Trace Module v3.5 (ETM)
•
Pre-Programmed Serial Bootloader
•
Temperature range -40 to 85 ºC
•
Single power supply 1.85 to 3.8 V
•
QFN64 package
32-bit ARM Cortex-M0+, Cortex-M3 and Cortex-M4 microcontrollers for:
• Energy, gas, water and smart metering
• Health and fitness applications
• Smart accessories
• Alarm and security systems
• Industrial and home automation
• www.energymicro.com/gecko
Preliminary
...the world's most energy friendly microcontrollers
1 Ordering Information
Table 1.1 (p. 2) shows the available EFM32WG940 devices.
Table 1.1. Ordering Information
Ordering Code
Flash (kB)
RAM (kB)
Max
Speed
(MHz)
48
48
48
Supply
Voltage
(V)
1.85 - 3.8
1.85 - 3.8
1.85 - 3.8
Temperature
(ºC)
-40 - 85
-40 - 85
-40 - 85
Package
EFM32WG940F64-QFN64
EFM32WG940F128-QFN64
EFM32WG940F256-QFN64
64
128
256
32
32
32
QFN64
QFN64
QFN64
Visit
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for information on global distributors and representatives or contact
sales@energymicro.com
for additional information.
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Preliminary
...the world's most energy friendly microcontrollers
2 System Summary
2.1 System Introduction
The EFM32 MCUs are the world’s most energy friendly microcontrollers. With a unique combination of
the powerful 32-bit ARM Cortex-M4, with DSP instruction support and floating-point unit, innovative low
energy techniques, short wake-up time from energy saving modes, and a wide selection of peripherals,
the EFM32WG microcontroller is well suited for any battery operated application as well as other systems
requiring high performance and low-energy consumption. This section gives a short introduction to each
of the modules in general terms and also shows a summary of the configuration for the EFM32WG940
devices. For a complete feature set and in-depth information on the modules, the reader is referred to
the
EFM32WG Reference Manual.
A block diagram of the EFM32WG940 is shown in Figure 2.1 (p. 3) .
Figure 2.1. Block Diagram
WG940F64/128/256
Core and Mem ory
ARM Cort ex™ M4 processor
wit h DSP ext ensions and FPU
Mem ory
Prot ect ion
Unit
Clock Managem ent
High Freq.
Cryst al
Oscillat or
Low Freq.
Cryst al
Oscillat or
High Freq.
RC
Oscillat or
Low Freq.
RC
Oscillat or
Energy Managem ent
Volt age
Regulat or
Brown-out
Det ect or
Back-up
Power
Dom ain
Volt age
Com parat or
Power-on
Reset
Flash
Program
Mem ory
RAM
Mem ory
Debug
Int erface
w/ ETM
DMA
Cont roller
Ult ra Low Freq.
RC
Oscillat or
32-bit bus
Peripheral Reflex Syst em
Serial Int erfaces
USART
Low
Energy
Uart ™
USB
UART
I/O Port s
Tim ers and Triggers
Tim er/
Count er
Low Energy
Tim er
Analog Int erfaces
ADC
LCD
Cont roller
Securit y
Hardware
AES
LESENSE
Real Tim e
Count er
I
2
C
Ext ernal
Int errupt s
Pin
Reset
General
Purpose
I/O
Pin
Wakeup
DAC
Pulse
Count er
Back-up
RTC
Wat chdog
Tim er
Analog
Com parat or
Operat ional
Am plifier
2.1.1 ARM Cortex-M4 Core
The ARM Cortex-M4 includes a 32-bit RISC processor, with DSP instruction support and floating-point
unit, which can achieve as much as 1.25 Dhrystone MIPS/MHz. A Memory Protection Unit with support
for up to 8 memory segments is included, as well as a Wake-up Interrupt Controller handling interrupts
triggered while the CPU is asleep. The EFM32 implementation of the Cortex-M4 is described in detail
in
ARM Cortex-M4 Devices Generic User Guide.
2.1.2 Debug Interface (DBG)
This device includes hardware debug support through a 2-pin serial-wire debug interface and an Embed-
ded Trace Module (ETM) for data/instruction tracing. In addition there is also a 1-wire Serial Wire Viewer
pin which can be used to output profiling information, data trace and software-generated messages.
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2.1.3 Memory System Controller (MSC)
The Memory System Controller (MSC) is the program memory unit of the EFM32WG microcontroller.
The flash memory is readable and writable from both the Cortex-M4 and DMA. The flash memory is
divided into two blocks; the main block and the information block. Program code is normally written to
the main block. Additionally, the information block is available for special user data and flash lock bits.
There is also a read-only page in the information block containing system and device calibration data.
Read and write operations are supported in the energy modes EM0 and EM1.
2.1.4 Direct Memory Access Controller (DMA)
The Direct Memory Access (DMA) controller performs memory operations independently of the CPU.
This has the benefit of reducing the energy consumption and the workload of the CPU, and enables
the system to stay in low energy modes when moving for instance data from the USART to RAM or
from the External Bus Interface to a PWM-generating timer. The DMA controller uses the PL230 µDMA
controller licensed from ARM.
2.1.5 Reset Management Unit (RMU)
The RMU is responsible for handling the reset functionality of the EFM32WG.
2.1.6 Energy Management Unit (EMU)
The Energy Management Unit (EMU) manage all the low energy modes (EM) in EFM32WG microcon-
trollers. Each energy mode manages if the CPU and the various peripherals are available. The EMU
can also be used to turn off the power to unused SRAM blocks.
2.1.7 Clock Management Unit (CMU)
The Clock Management Unit (CMU) is responsible for controlling the oscillators and clocks on-board the
EFM32WG. The CMU provides the capability to turn on and off the clock on an individual basis to all
peripheral modules in addition to enable/disable and configure the available oscillators. The high degree
of flexibility enables software to minimize energy consumption in any specific application by not wasting
power on peripherals and oscillators that are inactive.
2.1.8 Watchdog (WDOG)
The purpose of the watchdog timer is to generate a reset in case of a system failure, to increase appli-
cation reliability. The failure may e.g. be caused by an external event, such as an ESD pulse, or by a
software failure.
2.1.9 Peripheral Reflex System (PRS)
The Peripheral Reflex System (PRS) system is a network which lets the different peripheral module
communicate directly with each other without involving the CPU. Peripheral modules which send out
Reflex signals are called producers. The PRS routes these reflex signals to consumer peripherals which
apply actions depending on the data received. The format for the Reflex signals is not given, but edge
triggers and other functionality can be applied by the PRS.
2.1.10 Universal Serial Bus Controller (USB)
The USB is a full-speed USB 2.0 compliant OTG host/device controller. The USB can be used in Device,
On-the-go (OTG) Dual Role Device or Host-only configuration. In OTG mode the USB supports both
Host Negotiation Protocol (HNP) and Session Request Protocol (SRP). The device supports both full-
speed (12MBit/s) and low speed (1.5MBit/s) operation. The USB device includes an internal dedicated
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.
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Preliminary
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2.1.11 Inter-Integrated Circuit Interface (I2C)
The I C module provides an interface between the MCU and a serial I C-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.
2
The interface provided to software by the I C 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
2
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 Serial Bootloader
The bootloader presented in application note AN0003 is pre-programmed in the device at factory. Auto-
baud and destructive write are supported. 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 , 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.
TM
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.
2.1.18 Low Energy Timer (LETIMER)
The unique LETIMER , the Low Energy Timer, is a 16-bit timer that is available in energy mode EM2
in addition to EM1 and EM0. Because of this, it can be used for timing and output generation when most
of the device is powered down, allowing simple tasks to be performed while the power consumption of
the system is kept at an absolute minimum. The LETIMER can be used to output a variety of waveforms
TM
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