Two Wires and 30 Years : A Tribute and Introductory Tutorial to the I2C Two-Wire Bus

One of my earliest experiences with embedded systems design was back in the late 1980s working with a relatively unknown embedded controller designed by a U.K. manufacturer. This controller, the Scorpion-K4, featured a quite advanced object-based programming language that made it suitable for rapid prototyping. However, the most powerful features were derived from the intelligent use of another little-known hardware technology?a simple two-wire hardware bus that enabled a keypad, an alphanumeric liquid-crystal display (LCD), and multiple digital and analog I/O ports to be hooked up to a single K4 controller.