EFM32 Gecko MCUs are a family of mixed-signal 32-bit microcontroller integrated circuits from Energy Micro (now Silicon Labs) based on ARM Cortex-M CPUs, including the Cortex-M0+, Cortex-M3 and Cortex-M4.
Overview
EFM32 microcontrollers have a majority of their functionality available down to their deep sleep modes, at sub-microamp current consumption, enabling energy-efficient, and autonomous behavior while the CPU is sleeping.
An example of a deep sleep peripheral on EFM32 is the Low Energy Sensor Interface (LESENSE), which is capable of duty-cycling inductive, capacitive, and resistive sensors while autonomously operating in Deep Sleep mode. Another aspect of the Gecko MCUs is that the peripherals have a direct connection with each other, allowing them to communicate without CPU wake-up and intervention. This interconnect is known as the Peripheral Reflex System (PRS).
Functionality is available at the lower Stop and Shutoff energy modes. The Stop mode includes analog comparators, watchdog timers, pulse counters, I2C links, and external interrupts. In Shutoff mode, with 20–100 nA current consumption, depending on the product, applications have access to GPIO, reset, a real-time counter (RTC), and retention memory.
The EFM32 family consists of a number of sub-families, ranging from the EFM32 Zero Gecko, based on an ARM Cortex-M0+, to the higher performing EFM32 Giant Gecko and Wonder Gecko, based on Cortex-M3 and Cortex-M4 respectively. EFM32 technology is also the foundation for EFR32 Wireless Geckos, a portfolio of Sub-GHz and 2.4 GHz wireless system on a chip (SoC) devices.
Product families:
Key properties
The energy efficiency of the EFM32 MCU portfolio stems from autonomous operations in deep sleep modes, low active and sleep currents, and fast wakeup times. EFM32 devices claim to be constructed to reduce development cycles by being pin and software compatible, scalable across wide application requirements, and compatible with multiple development platforms. The wireless Gecko portfolio (EFR32) shares the same MCU architecture with both software and hardware (pin/package) compatibility.
Features
At a low level, the MCU can be broken down into eight categories: the core and memory, clock management, energy management, serial interfaces, I/O ports, timers and triggers, analog interfaces, and security modules.
Features of the MCU include:
Low-energy modes. Peripheral Reflex System (PRS), a peripheral interconnect system with eight triggers to handle task execution without CPU intervention. CPU: ARM Cortex-M series, from the Cortex-M0+ to the Cortex-M4. Clock rate: 4 MHz to 48 MHz. Low frequency and ultralow frequency clocks. Internal voltage regulators. Flash memory: 4 kB to 1024 kB. RAM: 2 kB to 128 kB. Serial digital interfaces: USART, low energy UART, I2C, and USB. Timer and triggers block of the MCU includes a CRYOTIMER, low energy pulse counter (PCNT), and backup real-time-counter (RTC). Analog modules: ADCs, DACs, operational amplifiers, and analog comparators. Hardware cryptographic engines and cyclic redundancy checks (CRCs). Up to 93 General-purpose Input/Output (GPIO) pins. Some variants have LCD controllers.
Design and development resources
Design and development resources include: a freeware Integrated Development Environment (IDE), performance analysis tools, configuration tools and utilities, compilers and development platforms, software stacks, reference code and design examples, application notes, training videos, and white papers.
Silicon Labs Simplicity Studio is a freeware, Eclipse-based development platform with graphical configuration tools, energy-profiling tools, wireless network analysis tools, demos, software examples, documentation, technical support and community forums. It also includes compiler tool options, including GCC for ARM, Keil, IAR Embedded Workbench, and other third-party tools.
Tools within Simplicity Studio IDE include the Advanced Energy Monitor (AEM) and the Network Debugger called “Packet Trace”. The Advanced Energy Monitor is an EFM32 tool that allows developers to do energy profiling while their application is running. It also claims to allow direct code correlation to optimize both hardware and software. The Network Debugger is a tool that allows developers using the wireless Gecko MCUs to trace network traffic and packets throughout nodes on the network.