A micro processor can be considered as the control and proces­sing unit of a small computer, capable of handling both arithmetic and logic data under control of a program. It utilizes the techno­logy of the Large Scale Integration (LSI) and a complete 4-bit, 8-bit LSI microprocessor can be built on a single chip. Its initial cost is low and as it uses a small number of ICs, the reliability is high. It also provides increased flexibility. Due to these advantages it can replace minicomputers and hardwired controllers. To make it suitable for N 1C of machine tool, it requires the addition of memory of data and control program, time-base logic and a set of input/output interface circuits to communicate with peripheral devices. The memory could be either ROM type (Read only Memory) or R/W (Read-Write Memory), also know as RAM (Random Access Memory).