Embedded systems are finding increasing application not only in domesticapplications but also in areas of industrial automation, automobiles, power electronics, defence and space equipments. Micro controllers are the basic building blocks for many embedded systems.In spite of revolutionary advances in the field of electronics,micro controllers play a major role in the design of embedded control systems duringthe past two decades. They are available in 8-bit, 16-bit and 32-bit versions and aremanufactured by a number of leading companies like Intel, Motorola, Philips, Hitachi,Atmen, Microchip, Dallas, Siemens etc., . They are available in the market withvarious configurations for different applications