SCOTTSDALE, Ariz.—A standards development group is exploring the feasibility of a new interface standard that would enable even multiple degree-of-freedom arrays of micro-electro-mechanical system (MEMS) sensors to use a simple common interface.
Such an interface—which would be used by accelerometers, magnetometers, gyroscopes, altimeters, compasses, proximity sensors and non-MEMS sensors like GPS, near field communication, fingerprint identification, and the touchscreen itself—would require agreement from all interested parties on what protocols need to be recognized, according to the MIPI Alliance. The organization recently announced an open "birds of a feather" group to investigate the requirements for integrating multiple sensors into mobile systems.
"Today it can take over a dozen pins on an SoC just to interface to all its sensors," said Satwant Singh, director of strategic planning at Lattice Semiconductor, and a founding member of the birds of a feather group. "Ideally you only need a few pins if vendors can agree on a common standard, which would greatly simplifying the design and cut the bill-of-materials cost of mobile devices with lots of sensors."
Singh showed a two-wire interface standard as an example of how up to 23-pins from an SoC could be eliminated with a universal multi-drop interface—a kind of network-for-sensors, instead of using I2S or SPDIF plus all the specialized PC board traces needed for hand-shaking, interrupts and enablement (see figure).
Today it takes up to 23 pins (top) on an SoC to manage all the MEMS sensors attached, but by drafting a universal interface, the MIPI Alliance hopes to reduce the required pins (click on image to expand).
Source: MIPI Alliance
The birds of a feather group announced its formation here at the MEMS Executive Congress 2012, sponsored by the non-profit MEMS Industry Group (MIG).
"Since MEMS is playing a defining roll in the integration of sensors on mobile devices, MIG recognizes the importance of investigating the requirements needed to address this rapidly growing space," said Karen Lightman, managing director of MIG. "The massive proliferation of sensors is driving the trend toward standardization of sensor interfaces."
One of the birds of a feather group's first actions will be to poll MIG's members in order to draw an accurate portrayal of the current-day sensor interface landscape. Next, the group will seek next-generation technical requirements for using dozens of simultaneous sensors, including the types of algorithms and APIs needed to perform both system-level sensor fusion and application-level analytics. Related stories: