Embedded World: Energy Micro announces 'lowest power' ARM Cortex-M4
Low power microcontroller firm Energy Micro has added ARM's DSP-enabled embedded processor to its range, the Cortex-M4F.
Dubbed EFM32 Wonder Gecko, there are 60 variants in the range, all with ARM's floating point unit (the F suffix), adding to the 180 Cortex-M3 and M0 devices the firm already sells.
"As of today, we have a complete pin- and code-compatible roadmap of processors, from the lower cost value line Zero Gecko through to Wonder Gecko variants incorporating sophisticated signal processing functionality," said Energy's CEO Geir Førre.
The firm's speciality is low-power peripherals, combined with autonomous hardware blocks that can complete peripheral-to-peripheral transactions with the core asleep.
Claimed minimum active current consumption in Energy's M4F is 180µA/MHz. Deep sleep with the real-time clock (RTC) running is 400nA, down to 20nA in shut-off, with wake-up as short as 2µs.
DSP capability broadens the firm's market.
"We have a customer in Israel that has designed a glass break detector," Andreas Koller, Energy's v-p or marketing, told Electronics Weekly. "When glass breaks you get a strong signal at 13kHz. To detect this you need a DSP, so you usually need a power wire. He can do FFT and really look at amplitudes around 13kHz without a wire."
Another customer, he said, is using the DSP to measure flow ultrasonically in a water meter, claiming it to be the first one to be battery powered, and another to replace an expensive sensor with DSP plus a cheap sensor.
The firm uses a 0.18µm low-leakage CMOS process. "A lot of announcements you see in the market are at smaller geometries. You pay the price in less-accurate analogue performance and higher leakage," claimed Koller.
The M4F comes with up to 256kbyte of flash and 32kbyte of RAM.
For sensor use, it includes the firm's 'Lesense' function block, a generic low energy sensor interface, used in the water meter, which can monitor a mix of up to 16 capacitive, inductive or resistive sensors independently of the processor core.
"This allows designers to maintain basic functionality while keeping the processor in sleep or shut-off mode for as long as possible," said Energy.
Samples are scheduled for Q3 2012.