Why would ultra low-power devices matter to gadget makers and spooks?
The highly desirable low-power characteristic of a microcontroller defines battery life: how long the device can run off a portable energy supply and how much performance can be squeezed out of it. While the operational current draw is useful, what engineers really want to know is the standby current, because this determines how much will effectively leak out when the processor is doing absolutely nothing apart from waiting for an interrupt to stir it.
Freescale, which has licensed the new M0+ core for its Kinetis L range of microcontrollers, is keeping such figures close to its chest; it will reveal its finalised specifications in Q2 2012.
York estimated that, at full operation, a third of the current draw will come from the processor core (the 9uA/MHz figure), a third from the flash memory and a third from the peripheral sensor circuitry.
"If it's not well under 50uA [per Mhz] I'll be very surprised," said York, commenting on the overall current draw of an M0+ core with memory and interface circuitry connected. This is a power consumption of the chip while running a maths benchmark, representing a real-world number-crunching scenario; York accused one rival of running a NOP loop – a piece of code that essentially doesn't do anything – as a benchmark to brag about high performance while using little power on a microcontroller.
The success of the M0+ core and its uptake as a ubiquitous data-tossing processor will depend heavily on how low the chip manufacturers can squeeze the standby current.
CIA, enter stage right
The director of the US's Central Intelligence Agency, David Petraeus, speaking at a summit this month on intelligence gathering and engineering, touched on the concept of "an internet of things" - the notion of networking appliances and other objects together using such tiny, low-power radio-linked embedded chips to make to controlling gear easier (and monitoring people a piece of cake).
"In the digital world, data is everywhere, as you all know well. Data is created constantly, often unknowingly and without permission. Every byte left behind reveals information about location, habits, and, by extrapolation, intent and probable behaviour," said Petraeus.
"The number of data points that can be collected is virtually limitless — presenting, of course, both enormous intelligence opportunities and equally large counterintelligence challenges."
The spy boss was chiefly concerned with the huge amounts of data that can be collected from American citizens who intend to become CIA agents – in an age when parents set up Twitter and Tumblr accounts for their newborns, managing the identities of future operatives suddenly becomes non-trivial.
However, he went on to wax lyrical over smart sensors: "As you all know, exploiting the intelligence opportunities — which is an easier subject to discuss in an unclassified setting than the counterintelligence challenges — will require a new class of in-place and remote sensors that operate across the electromagnetic spectrum. Moreover, these sensors will be increasingly interconnected."
Referring to item tagging, sensors and wireless networks, and embedded engineering, Petraeus added that the proliferation of tiny, portable and intelligent sensor networks will appeal to his organisation. He said:
Items of interest will be located, identified, monitored, and remotely controlled through technologies such as radio-frequency identification, sensor networks, tiny embedded servers, and energy harvesters — all connected to the next-generation internet using abundant, low cost, and high-power computing — the latter now going to cloud computing, in many areas greater and greater supercomputing, and, ultimately, heading to quantum computing.
In practice, these technologies could lead to rapid integration of data from closed societies and provide near-continuous, persistent monitoring of virtually anywhere we choose.
You can see alpha-grade low-power smart sensor chips in action on the Freescale stand at DESIGN West in San Jose, California next week. NXP is also a Cortex-M0+ licensee. ®