The I²C two-wire bus is still as popular today as when Philips originally invented it in 1982. Initially operating at 100KHz, the latest incarnation, version 7 (2021) Ultra-Fast-mode (UFm), now clocks at 5MHz—making it fast enough for most medium-speed peripherals, including digital I/O, GPIO, keyboards, keypads, and sensors.
Fibre optic networks bring the promise of fast broadband to new customers all around the world. It increasingly reaches new limits, but to provide a guaranteed level of service, that bandwidth must be managed effectively. A significant factor to that effectiveness is how it interfaces with other network equipment running over copper cable.
The 2-wire I²C bus is an incredibly useful way to add all kinds of low-speed I/O besides I²C while simplifying designs and trace routing.
