What is Central Processing Unit or microprocessor?

Answer 1

• A CPU is the electronics that perform the instruction processing functions of a computer. It does not include any memory (except for perhaps a small set of high speed operand/result registers and/or high speed microcode ROM), memory management unit, mass data storage, or input/output devices. It does include the CU (control unit, which fetches and decodes instructions and handles interrupts/exceptions/traps) and the ALU (arithmetic logic unit). Depending on implementation technology the size of a CPU can vary from many large electronics racks to a single circuit board to a small part of an integrated circuit.
• a microprocessor is an electronic implementation (in a small number of integrated circuits, typically just one integrated circuit) of a CPU and often other units that improve CPU performance if they are in very close proximity to the CPU (e.g. cache memory, memory management unit).
• a microcontroller is an electronic implementation (in one integrated circuit) of a complete computer, but very limited computer usually programmed to control an appliance or other system.
• a system on a chip is an electronic implementation (in one very large integrated circuit) of a complete computer system including all external device interface circuits (some of which may be implemented as microcontrollers, etc.).