Silicon Labs has introduced 32-bit microcontrollers (MCUs) based on the ARM Cortex-M0+ processor. The EFM32 Zero Gecko MCU family is designed to achieve the lowest system energy consumption for a wide range of battery-powered applications such as mobile health and fitness products, smart watches, activity trackers, smart meters, security systems and wireless sensor nodes, as well as battery-less systems powered by harvested energy.
The new Zero Gecko family is the latest addition to the EFM32 Gecko portfolio pioneered by Energy Micro and includes 16 cost-effective MCU products designed from the ground up to enable the lowest possible energy consumption for connected devices enabling the Internet of Things (IoT).
The EFM32 Zero Gecko MCUs feature a sophisticated energy management system with five energy modes that enable applications to remain in an energy-optimal state, spending as little time as possible in the energy-hungry active mode. In deep-sleep mode, Zero Gecko MCUs have a 0.9 µA standby current consumption with a 32.768 kHz RTC, RAM/CPU state retention, brown-out detector and power-on-reset circuitry active. Active-mode power consumption scales down to 110 µA/MHz at 24 MHz with real-world code (prime number search algorithm) executed from flash. Current consumption is less than 20 nA in shut-off mode. The EFM32 MCUs further reduce power consumption with a 2-microsecond wakeup time from standby mode.
As with all EFM32 Gecko products, the Zero Gecko MCUs include a best-in-class energy-saving feature called the Peripheral Reflex System (PRS) that significantly enhances system-level energy efficiency. The PRS monitors complex system-level events and allows different MCU peripherals to communicate directly with each other and autonomously without involving the CPU. Leveraging the PRS, an EFM32 MCU can watch for a series of specific events to occur before waking the CPU, thereby keeping the Cortex-M0+ processor core in an energy-saving standby mode as long as possible and reducing overall system power consumption.
The EFM32 Zero Gecko MCUs feature many of the power-saving precision analogue peripherals included in Silicon Labs’ Tiny Gecko, Giant Gecko and Wonder Gecko devices. These low-energy peripherals include an analogue comparator, a supply voltage comparator, an on-chip temperature sensor and a 12-bit analogue-to-digital converter (ADC) with 350 µA current consumption at a 1 MHz sample rate.
The EFM32 Zero Gecko devices are the only Cortex-M0+ MCUs on the market that integrate a programmable current digital-to-analog converter (IDAC). This on-chip precision-analogue IDAC generates a biasing current from 0.05-64 µA with only 10 nA overhead. The IDAC provides an accurate bias and/or control capability for companion ICs and other external circuits including amplifiers, sensors, Wheatstone bridges and resistor ladders, thereby eliminating the need for external power amplifier components for many cost-sensitive applications.
The Zero Gecko devices are also the only Cortex-M0+ MCUs containing a 128-bit Advanced Encryption Standard (AES) hardware block. With this built-in hardware AES encryption acceleration support, the Zero Gecko MCUs provide an ideal companion for RF transmitters and transceivers used in connected device applications for the Internet of Things.
“The Internet of Things is a huge and exciting market made possible by low-cost, battery-powered connected devices and wireless sensor nodes that sip nanoamps of energy,” said Geir Førre, senior vice president and general manager of Silicon Labs’ microcontroller products. “The IoT market requires battery-friendly Cortex-M0+ based MCUs that save both energy and system cost. Our new EFM32 Zero Gecko MCUs enable developers to create embedded systems that are four times more energy-efficient than possible with other Cortex-M0/0+ MCUs.”
The EFM32 Zero Gecko family is pin- and software-compatible with Silicon Labs’ broad portfolio of nearly 250 EFM32 Gecko MCU products. This compatibility provides developers with a cost-effective, energy-friendly entry point to higher-performance Gecko devices including the new Wonder Gecko based on the ARM Cortex-M4 core featuring a full DSP instruction set and dedicated floating point unit (FPU).