microprocessor is a computer processor that incorporates the functions of a computer‘s central processing unit (CPU) on a single integrated circuit(IC). The microprocessor is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. Microprocessors contain both combinational logic and sequential digital logic. Microprocessors operate on numbers and symbols represented in the binary numeral system.

Its a silicon-chip that contains CPU. In personal computer’s world the term microprocessor and CPU uses interchangeably.


The microprocessor is the heart of any normal computer whether it is desktop, laptop, or server machine. The microprocessor contains all or most of the CPU functions. And it goes into motion the time you turn on your computer. It contains million of very small components that includes transistor, registers, and diodes that works together.

Microprocessors help to do everything from writing to searching the Web. A typical microprocessor operations include adding, subtracting, comparing two numbers, and fetching numbers from one area to another.

Microprocessors were invented in the 1970s for use in embedded systems. The majority are still used that way, in such things as mobile phones, cars, military weapons, and home appliances.

Some microprocessors are microcontroller,so small and inexpensive that they are used to control very simple products like flashlights and greeting cards that play music when you open them. A few especially powerful microprocessors are used in personal computers.so small and inexpensive that they are used to control very simple products like flashlights and greeting cards that play music when you open them. A few especially powerful microprocessors are used in personal computers.

Working Of Microprocessor-

To understand how a microprocessor works, it is helpful to look inside and learn about the logic used to create one. In the process you can also learn about assembly language — the native language of a microprocessor — and many of the things that engineers can do to boost the speed of a processor.
A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things:

Using its ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operations like addition, subtraction, multiplication and division. Modern microprocessors contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.

A microprocessor can move data from one memorylocation to another.

A microprocessor can make decisions and jump to a new set of instructions based on those decisions.

There may be very sophisticated things that a microprocessor does, but those are its three basic activities. The following diagram shows an extremely simple microprocessor capable of doing those three things:
This is about as simple as a microprocessor gets. This microprocessor has:


An address bus (that may be 8, 16 or 32 bits wide) that sends an address to memory

data bus (that may be 8, 16 or 32 bits wide) that can send data to memory or receive data from memory

An RD (read) and WR (write) line to tell the memory whether it wants to set or get the addressed location

clock line that lets a clock pulse sequence the processor

reset line that resets the program counter to zero (or whatever) and restarts execution

Let’s assume that both the address and data buses are 8 bits wide in this example.
Here are the components of this simple microprocessor:

Registers A, B and C are simply latches made out of flip-flops. (See the section on “edge-triggered latches” in How Boolean Logic Works for details.)

The address latch is just like registers A, B and C.

The program counter is a latch with the extra ability to increment by 1 when told to do so, and also to reset to zero when told to do so.

The ALU could be as simple as an 8-bit adder (see the section on adders in How Boolean Logic Works for details), or it might be able to add, subtract, multiply and divide 8-bit values. Let’s assume the latter here.

The test register is a special latch that can hold values from comparisons performed in the ALU. An ALU can normally compare two numbers and determine if they are equal, if one is greater than the other, etc. The test register can also normally hold a carry bit from the last stage of the adder. It stores these values in flip-flops and then the instruction decoder can use the values to make decisions.

There are six boxes marked “3-State” in the diagram. These are tri-state buffers. A tri-state buffer can pass a 1, a 0 or it can essentially disconnect its output (imagine a switch that totally disconnects the output line from the wire that the output is heading toward). A tri-state buffer allows multiple outputs to connect to a wire, but only one of them to actually drive a 1 or a 0 onto the line.

The instruction register and instruction decoder are responsible for controlling all of the other components.


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