Abstract : A complete system usually consists of at least one microcontroller and other peripheral devices such as memories and I/O expanders. The cost of connecting the various devices within the system must be minimized
• A system that performs a control function doesn’t require high-speed data transfer
• Overall efficiency depends on the devices chosen and the nature of the interconnecting bus structure.
In order to produce a system to satisfy these criteria, a serial bus structure is needed. Although serial buses don’t have the throughput capability of parallel buses, they do require less wiring and fewer IC connecting pins. However, a bus is not merely an interconnecting wire, it embodies all the formats and procedures for communication within the system. Devices communicating with each other on a serial bus must have some form of protocol which avoids all possibilities of confusion, on the devices connected to it, otherwise modifications or improvements would be impossible. A procedure has also to be devised to decide which device will be in control of the bus and when. And, if different devices with different clock speeds are connected to the bus, the bus clock source must be defined. All these criteria are involved in the specification of the I 2 C-bus.