Sept. 04, 2025 –
Earlier this year, MIPI established the I/O Bridges Working Group, which was promoted from a 2024 MIPI Birds of a Feather (BoF) group, to explore the need for standardized hardware and software solutions to support I/O bridge use cases in computing segments.
We sat down with Aruni Nelson, I/O Bridges Working Group chair, to learn more about the new group and its near-term plans for the development of I/O bridge specifications.
An I/O (Input/Output) bridge is a device that exposes one or more native I/O protocols/interfaces over a single I/O link. This bridge acts as a translator, aggregator and manager of data and control signals between a host system and multiple I/O interfaces. This allows the host system to communicate with multiple devices using various protocols over a single I/O link and allows the host system to offload the management of the bridged I/O interfaces.
For example, an I3C bridge can enable an I3C controller in a host system to access multiple I2C buses and devices without the controller having native multi-bus I2C support. Similarly, bridging SPI, UART and GPIO over I3C can reduce system pin count, simplify printed circuit board (PCB) routing, lower power consumption and consolidate device management into a single high-performance interconnect.
By multiplexing multiple I/O protocols over one physical I/O bus, the bridge can significantly reduce the number of physical pins required on systems on chips (SoCs), streamline system design and extend the life of existing legacy peripherals without re-design.
The rapid expansion of IoT, embedded systems and connected devices has created a strong need for standardized, efficient ways to connect legacy peripherals with modern, high-performance interconnects. Many computing platforms still rely on multiple I2C, SPI, UART and GPIO interfaces, yet system designers are under pressure to reduce pin count, lower power consumption and simplify PCB layouts.
Currently system designers are reliant on proprietary solutions to convert one or more I/O protocols to another I/O protocol, requiring custom hardware and software that limits scalability, interoperability and long-term support. Standardized bridge solutions can facilitate interoperability, scalability and adoption of fast-moving technologies.
At a high level, the group is focused on developing a standardized framework for bridging multiple legacy and modern I/O protocols over a single I/O interface of choice. Our three primary objectives are...