Jon Titus Blog

You never know where new chips based on an ARM CPU will pop up. Energy Micro AS of Oslo, Norway has used an ARM Cortex-M3 CPU in its Gecko processor family and just released a new low-power EFM32G microcontroller (MCU). The company's announcement of the new MCU notes the EFM32G consumes less than 180 μA per MHz as it runs real-world code from flash memory. The company claims, "...the MCU achieves the lowest active-mode current consumption of any microcontroller. Its standby current consumption is also the lowest, at typically 900 nA while running real time clock, power-on reset, brown-out detector and full RAM and CPU retention, and less than 20 nA in its deepest sleep mode. Furthermore, the microcontroller’s start-up time of less than 2 μs is the industry’s fastest." Find Energy Micro at www.energymicro.com.

Other power specifications in the Energy Micro information include: A 4x40 segment LCD controller (<900 nA), an 8-channel 12-bit 1M sample/sec ADC (<200 μA); a brown-out detector (<100 nA), a 32-kHz real-time counter (50 nA), and a UART capable of 9600 bps at 100nA.

Those low-power requirements should give designers another option for battery-powered circuits used in utility meters, home and building automation, and alarm systems. Military-equipment manufacturers might look at the EFM32G for low-power expendable or one-shot applications such as intruder monitors, leave-behind sensors and monitors, clip-on medical instruments, and miniature robotic devices that run from two or three AA batteries.

Energy Micro has two development kits, the EFM32 Gecko Development Kit (EFM32-G2xx-DK) and the EFM32 Gecko Development Kit (with LCD support, EFM32-G8xx-DK). For the software portion of the kits, the company notes developers can use compilers and debuggers from IAR Systems, Segger, Keil, Hitex or they can use the GNU Compiler Collection for ARM. The kit comes with "a board-support package and device-support library, and development support for major tool chains." I didn't see information about a memory- or time-limited version of development tools that come as part of the kit, though. I wonder how easy it is to get these tools up and running with a Gecko dev kit? Kit price: $US 299. Energy Micro has representatives worldwide and plans to appoint a US distributor soon.

Developers can download the 445-page Reference Manual for the EFM32G Microcontroller Family and the 135-page Cortex-M3 Reference Manual for the EFM32G Microcontroller Family. Look for "Reference Manuals" under the "Downloads" tab on the Energy Micro Web site.

The EFM32G operates from a single power source between 1.8 and 3.8V over the –40 to +85 degree (Celcius) temperature range. The microcontrollers provide up to 128 Kbytes of flash memory and as many as 16 Kbytes of RAM. --Jon Titus