The hardware world constantly asks questions, but one of the most important is how low energy consumption can go. While talking about a couple of watts in smartphones and tablets is fine, the so-called "Internet of Things" requires designs that work for months, or why not years, on a single battery. The folks at Atmel plan to take this idea to the extreme with their new SAM L21 controller, which operates for more than ten years on a single charge.
Why Low Power Matters
If you like electronics or have a preference for DIY projects, sooner or later you'll cross paths with some microcontrollers. Saying "Arduino" these days invokes a certain generic profile, because each of its models uses different chips. I personally lean toward the ATmega32U4, very popular for converting protocols in old keyboards, but that's just one of many uses. With the advance of the "Internet of Things", placing chips in unusual places represents a huge challenge, not so much due to size but due to energy concerns. Nobody wants to climb a ladder every six months to change the internal battery in a smart lamp, or use sensors that devour batteries like candy. Controllers must consume less, and that's where Atmel is headed with its new SAM L21 series.
Impressive Demo and Specs
The demo that Atmel performed at the last CES was impressive. Turning one of these chips into an AM transmitter powered by the heat of the body human amazed more than one, but if we look closely at the specifications we can see that the company has entered a different category. Most microcontrollers need between 120 and 160 microamps per MHz to work properly, but the SAM L21 cuts those numbers down to a floor of 35 microamps per MHz in active mode, and less than 200 nanoamps when entering sleep-like modes. If we interpret this in terms of battery life, Atmel says it can extend beyond ten years, provided it has adequate capacity.
Inside the SAM L21
As we mentioned in the title, the Atmel SAM L21 uses ARM technology, a Cortex-M0+ core to be precise, whose frequency reaches 48 MHz. Its flash memory is 256 kilobytes, accompanied by up to 40 kilobytes of SRAM (varies by model), and there is also an additional 8-kilobyte module that operates in the lowest power modes. Now, for those who want to know the operating voltage of the SAM L21, Atmel has left that data out of the general announcement, but the PDF with the complete datasheet (link below) indicates between 1.62 and 3.63 volts. The potential of a product like the Atmel SAM L21 is gigantic. I'm sure many developers are imagining novel ways to power the chip, and in that regard there is already good news: The Xplained Pro evaluation kit is available, with a price of $54.
