A Microprocessor (MPUs) is a system-on-chip that you can find in all kinds of embedded systems. MPUs integrate a processor core, memory, and several programmable peripherals such as input/output ports, timers, analogue-to-digital converters, digital-to-analogue converters, parallel and serial communications, and more onto a single chip. This higher integration allows an engineer to reduce the size, cost and power consumption (for battery powered, efficient applications). This makes the microprocessors are found in a wide range of applications, such as process control and communication systems. The objective of studying Microprocessors and its Interfacing is to understand the concepts, terminology and technology used in the advanced microprocessors, and study in this book includes the Internal architecture, programming concepts, memory and I/O interfacing of 8085, 8086, Pentium and also the variants on chip peripherals and interfacings.