Organisation of a CPU; Input/Output devices Central Processing Unit (CPU) The CPU is the control center of a computer, responsible for carrying out i...
Central Processing Unit (CPU)
The CPU is the control center of a computer, responsible for carrying out instructions and managing the entire system. It performs the following tasks:
Decodes instructions from memory (RAM).
Executes instructions by calling other components.
Controls the operation of input/output (I/O) devices.
Provides a platform for other components to communicate with it.
Input/Output (I/O) devices
I/O devices allow a computer to interact with the outside world, such as the keyboard, mouse, hard drive, and network. These devices provide a means for users to input data and instructions, and for the computer to send information and results to other systems.
Structure of an I/O device:
An I/O device consists of two main components:
Control register: This register stores the address of the next instruction to be sent to the device.
Data register: This register holds the data to be sent to the device.
I/O communication:
The CPU sets the address of the control register in the device.
The device reads the data from its data register.
The CPU sets the address of the data register in the CPU.
The device writes the data to the specified address.
Examples:
Keyboard: The CPU reads the key pressed from the keyboard and updates the control register.
Hard drive: The CPU reads data from the hard drive and displays it on the monitor.
Network card: The CPU sends network data to other devices on the network.
Flowcharts:
Flowcharts are visual representations of how a system flows information. They can be used to show the sequence of steps involved in processing an instruction, including data transfer between the CPU and I/O devices.
Importance of I/O devices:
I/O devices are essential for the proper functioning of a computer system. They allow the CPU to interact with the outside world and respond to user input and system events. Without I/O devices, a computer would be unable to receive instructions, display information, and perform other tasks