What is Address Bus, Data Bus & Control Bus in Computer?
If you’re reading this tutorial by skipping the previous tutorial then I strongly recommend that you read and understand the previous tutorial first. It is a part of our computer tutorials & fundamentals series. In the Previous tutorial, we discussed the basic concept of Buses on a computer. We can also say that the previous tutorial is an introduction tutorial about buses so you're aware of buses…
Let’s come on topic…Today we're going to describe Address Bus, Data Bus, and Control Bus on a computer.
What is Address Bus in Computer?
In a computer, the address bus is used by the CPU (Central processing unit) to send the address of the memory locations or the input/output port that is to be accessed at the instant. The Address bus is unidirectional bus i.e. the address of the memory locations can be transferred in one direction only, and that is from the CPU to the required port or location.
What is the address bus used for?
Whether it is a read operation or a write operation the CPU (Central processing unit) of the computer calculates the address of the required data and sends it on the data bus for the execution of the required operation. The maximum number of memory locations that can be accessed in a system is determined by the number of lines of an address bus.
An address bus of n lines can be addressed at most 2n locations directly. Thus a 16-bit address bus can allow access to 2 16-bit or 64 K Byte of memory.
why an address bus is called a unidirectional bus?
Address Bus is called a unidirectional bus because the CPU is used to send memory location to input/output ports. input/output device won't send anything back to cpu that's why the address bus is called the unidirectional bus.
What is a Data Bus in a computer?
In a computer, the data bus is used to carry the data and instructions from the CPU to memory and peripheral devices such as the mouse, keyboard, etc, and vice versa. This data bus is bidirectional. It's one of the most important parts of the connection to the CPU (Central Processing Unit) because all the program instructions and every byte of data must travel across the bus at some point.
The size of the data bus is measured in bits. The data bus size has much influence on the computer architecture because the important parameters of it like word size, the quantum of data, etc. are determined and manipulated by the size of the data bus.
Generally, a microprocessor is called an n-bit processor. Thus as the CPU became more advanced, the data bus grew in size. A 64-bit data bus can transfer 8 bytes in every bus cycle and thus its speed is much faster as compared to the 8-bit processor that can transfer one byte in every bus cycle.
why the data bus is called bidirectional?
Data Bus is called a bidirectional bus because it carries the information and data from the CPU to memory and vice versa memory to CPU. it can transmit data in both directions that why the data bus is called a bidirectional bus.
What is a Control Bus in a computer?
A control bus contains various individual lines carrying synchronizing signals that are used to control. Various peripheral devices are connected to the CPU. The common signals that are transferred to the control bus from CPU to devices and vice versa are memory read, memory writes, I/O read, I/O write, etc.
Signals are designed, keeping in mind, the design philosophy of the microprocessor and the requirements of the various devices connected to the CPU. So keep in mind that different types of microprocessors have different control signals. See below for a better understanding.
Image Source
Have a Good Day!!!