I3C sensor interface embraces mobile
MIPI claims that digital interfaces currently available, such as I2C and SPI, are too numerous, causing fragmentation, and do not use power efficiently for communication with sensors, which can limit applications and scalability.
The specification was developed with participation of many companies from across the sensor and mobile ecosystems, MIPI said. Companies working in the MIPI Alliance Sensor Working Group include AMD, Audience, Broadcom, Cadence, Intel, InvenSense, Lattice, MediaTek, Mentor Graphics, Nvidia, NXP, STMicroelectronics, Synopsys, Qualcomm, QuickLogic, ZMDI, and others. MIPI has about 275 members in total.
MIPI said that the term SenseWire will be used to describe the application of I3C in mobile devices and the use of the I3C interface for mobile devices connecting to a set of sensors, directly or indirectly.
In general SenseWire incorporates and unifies key attributes of I2C and SPI while improving the capabilities and performance of each approach with a comprehensive, scalable interface and architecture. The specification has also tried to anticipate sensor interface architectures that mobile, mobile-influenced, and embedded-systems industries will need in the future. I3C should help equipment developers combine multiple sensors from different vendors while having them communicate at low energy and therefore supporting longer battery life.
The technical features of the MIPI I3C specification include a two-pin interface that is backward compatible with the I2C standard and provides data throughput capabilities comparable to SPI.
I3C supports in-band interrupts within the 2-wire interface, which reduces device pin count and signal paths, and facilitates incorporation of more sensors in a device. On standard CMOS I/O, it supports a minimum data rate of 10Mbps with options for higher performance high-data-rate (HDR) modes, offering a substantial leap in performance and power efficiency compared to existing options. It also offers multimaster support, dynamic addressing, command-code compatibility and a uniform approach for advanced power management features, such as sleep mode.
"The steadily increasing use of sensors in wireless devices is driving innovation of new and exciting applications for all types of products, yet incorporating numerous sensors in end-user devices is a serious pain point," said Joel Huloux, chairman of the board of MIPI Alliance, in a statement. "SenseWire brings a long-awaited, standardized solution to these difficult problems."
“The MIPI I3C specification will have a lasting impact. It addresses the need for a standardized interface that ensures low-power operation in microcontrollers — across application, industry and market. Such broad applicability should produce direct benefits to wirelessly connected wearables, toy and gaming devices, healthcare products, and industrial equipment — applications that are the bedrock of the Internet of Things," said Karen Lightman, executive director of MEMS Industry Group.
The I3C specification is scheduled for working group completion by the end of 2014 and ratification and approval by the MIPI Alliance board of directors and publication in the first quarter of 2015.