Microprocessors : What is a microprocessor?

A microprocessor is the fundamental computing device inside any computer system.

It is a programmable, multipurpose, clock-driven, register based device that is used to process data. It is designed as a single integrated chip, used as a CPU to perform computations.

A microprocessor takes binary input, processes the data, and then produces binary output as result.

Unlike microcontrollers, microprocessors don’t have any memory integrated inside them. However, they do have internal registers for data storage. But since they do not have integrated memory, they cannot be used as standalone components.

Microprocessors have three mains components :

1. Arithmetic & Logic Unit
2. Control Unit
3. Register Set

Block diagram of a microprocessor

Arithmetic Logic Unit :

• Responsible for performing arithmetic and logical operations on data
• Most vital part of microprocessor
• Instructions are decoded and then given to the ALU which then performs operations accordingly
• n bit microprocessor = n bit operations = n bit ALU

Control Unit

• Responsible for managing the flow of data and information around the microprocessor
• Generates control signals for operations and instructions
• It can be either Hardwired or microprogrammed
• For normal processing of instructions different control signals are required to be activated at different times
• Control unit uses clock signals to coordinate and manage the internal operations of a microprocessor

Register Set

• Set of flip flops used to store 1 bit data values
• Used to store information related to processing and operations inside a microprocessor
• It has different registers for different purposes
• The capacity of registers depend on the microprocessor

Characteristics of a microprocessor

1. Word Length — The total maximum number of bits that can be processed by a microprocessor in one clock cycle. It can vary from 4 bits to 64 bits. It depends on the width of the data bus.
2. Clock speed — It is the speed at which instructions at executed by the microprocessor. It is the number of cycles that a CPU can execute, per second.
3. Instruction set — It is the set of all the instructions that can be executed on a microprocessor.