Abstract :
Microcontrollers, by their very nature and intention, often possess limited on-chip resources. Despite this, designers still prefer them because of their low cost and efficient architecture for embedded controller applications. This has resulted i n most MCU- based systems consisting of one or more additional chips, often memory, I/O expanders, or specialized devices. Additionally, functions are implemented external to the MCU because of technology performance limitations, in particular analog circuits, or high pin-count functions such as multiplexing display drivers, or limited volume applications that would be prohibitively expensive to implement on the MCU silicon. System designers must decide which method is the best to use to interface those additional components into the system design while meeting the goals of the application. Two primary methods have emerged- parallel bus systems and serial bus systems.
