MIPI Alliance Reports Successful Plugfest of Three I3C Specifications

September 28, 2023 by Jake Hertz

This year’s Plugfest helped validate I3C and build out its ecosystem amongst some of the industry’s leaders.

Today’s electronic devices rely heavily on data and communication with other electronic systems, necessitating newer, better communication standards and protocols. One such protocol is the Improved Inter-Integrated Circuit (I3C) standard, which builds off of I2C to offer unprecedented reliability and features.


Participants at this year’s I3C Plugfest.

Participants at this year’s Plugfest. Image used courtesy of the MIPI Alliance


In June, the MIPI (mobile industry processor interface) Alliance organization held its annual Plugfest,  with this year's event representing a significant milestone for the I3C standard. And this week the MIPI Alliance announced the results of that Plugfest. So what happened at this year’s Plugfest, and what is I3C anyway?


MIPI’s Plugfest Details

The I3C Plugfest is a notable event organized by MIPI aimed at advancing the adoption and interoperability of I3C designs. Conducted this year in San Jose, California, the event witnessed participation from 26 I3C implementers representing 10 companies, including industry leaders like Intel, STMicroelectronics, and Microchip Technology.

This year’s Plugfest focused on rigorous interoperability testing across multi-vendor devices, covering initial to advanced stages of I3C designs. As part of this, the event involved a confidential environment where participants could test the interoperability between multi-vendor controllers and target devices. 

Specifically, three key I3C specifications were put to the test:

  • MIPI I3C: The full-fledged MIPI I3C specification serves as the comprehensive version designed to be the successor to I2C. It incorporates key attributes from traditional I2C and SPI interfaces, offering a robust, flexible upgrade path.
  • MIPI I3C Basic: A streamlined, royalty-free subset of the MIPI I3C that bundles the most commonly needed features. It is designed to be simpler and easier to implement, making it ideal for less complex systems or for companies looking to transition from I2C to I3C without a steep learning curve. MIPI I3C Basic has been adopted into JEDEC's Sideband Bus and DDR5 standards, indicating its utility in a range of applications.
  • MIPI Debug for I3C: This specification focuses on debugging and testing capabilities. It provides a bare-metal interface that allows system designers to debug and test application processors and other power-managed components across a system via the I3C interface. 

With each of these specifications serving different needs and use cases, MIPI views the Plugfest as a truly comprehensive testing ground for I3C's versatility.


I3C and How it Works

I3C is a high-speed, low-power bus interface developed by the MIPI Alliance. Designed as an evolutionary step over the traditional I2C and SPI interfaces, I3C aims to provide a unified, scalable solution for connecting peripherals to an application processor.


An I3C data bus.

An I3C data bus. Image used courtesy of NXP Semiconductors


I3C operates on a two-wire interface, similar to I2C, consisting of a data line (SDA) and a clock line (SCL). Unlike I2C, however, it incorporates several advanced features that set it apart. 

For instance, I3C supports a higher data rate, up to 12.5 Mbps, compared to I2C's maximum of 1 Mbps. It also introduces new types of bus events and timing modes, such as In-Band Interrupts (IBI) and Common Command Codes (CCC), which allow for more efficient communication between devices. Further, I3C employs a dynamic addressing scheme, enabling hot-joining of devices, and supports multi-master configurations, which make the bus more resilient and flexible.


The Importance of I3C and MIPI’s News

The significance of I3C lies in its ability to serve as a comprehensive interface for a wide array of applications, from smartphones and wearables to automotive systems. Its high data rate and low power consumption make it ideal for battery-operated devices where energy efficiency is crucial, while its backward compatibility with I2C ensures that existing systems can transition to I3C without a complete overhaul.

The successful completion of the Plugfest, on the other hand, serves as a significant milestone for the I3C ecosystem. It not only validates the interoperability of I3C devices but also accelerates its adoption as a standard. As industries continue to demand faster, more efficient communication protocols, the I3C standard, backed by successful interoperability tests, is well-positioned to meet these challenges.