Internal Hardware Components

processor ○ main memory ○ address bus ○ data bus ○ control bus ○ I/O controllers

Main memory ● Includes RAM (random access memory) and ROM (read only memory) ● Stores program instructions and frequently used data ● Usually much faster than secondary storage

A bus is a set of parallel wires that connect computer components and allow data, addresses, and control signals to be transmitted between them. Buses allow components such as the CPU, memory, and I/O devices to communicate.

The address bus is a set of parallel wires used to carry memory addresses from the processor to memory or I/O devices.

Specifies which memory location or device the CPU wants to access. Is unidirectional (from CPU to memory/devices). The width of the address bus determines the maximum amount of memory that can be addressed.

The data bus is a set of parallel wires used to transfer data between the processor, memory, and input/output devices.

Carries actual data and instructions. Is bidirectional, meaning data can travel to and from the CPU. The width of the data bus affects how much data can be transferred at once.

The control bus is a set of wires that carry control signals between the processor, memory, and other hardware components.

Sends signals such as read, write, interrupt, and clock signals. Coordinates and controls the operations of the computer system. Ensures components know when to send or receive data

Pieces of hardware that control the communication of data between the processor and external hardware devices such as keyboards, mice and monitors

Provide an interface between the CPU and peripherals (e.g., keyboard, printer, disk). Handle data transfer to and from devices. Allow the CPU to communicate with many different devices efficiently.

hardware components must exchange data and instructions for the system to work. The processor (CPU) needs to fetch instructions from main memory (RAM). Data may need to be sent to output devices or received from input devices. The CPU must know where data is stored and when it can be read or writte

The CPU sends the memory address along the address bus. The CPU sends a read signal along the control bus. The RAM sends the requested data back along the data bus.

Stores Data and Instructions separately in buses and memory . the instruction memeory can be a read only mempry to ensure it is cannot be altered Embedded systems such as digital signal processing (DSP) systems use Harvard architecture processors extensively.

Stores Data AND Instructions together Used extensively in general purpose computing systems.

The PC loads the memory address of the next instruction. The memory address is copied to the MAR The PC loads the next memory address of the next instruction The memory address, and a read instruction is copied to the MAR The MAR accesses the memory address location, executing the read instruction. The data and instructions (processor instruction set) stored, and now read, are passed to the MDR The MDR brings the data and instructions (processor instruction set) back to the CPU The contents are copied to the CIR ready to be decoded.

Decode The processor instruction set stored in the CIR are decoded by the Control Unit: Instructions (opcode) Data (operand) Addressing mode: immediate or direct Once the instructions and data have been decoded they are passed to the ALU ready to be executed.

The ALU processes the logical/arithmetic operation on the data The outcome can be: Stored in the accumulator Stored back in main memory Output

The role of the ALU is to perform arithmetic and logic operations. Arithmetic operations are mathematical operations like addition, logic operations include AND, OR and XOR

Manages and coordinates the activities of the processor. Think of the control unit as a traffic controller!

The clock generates a signal that is used to synchronise the operation of the processor and the movement of data around the other components of the computer

Tiny parts of memory hat can be used by the CPU to hold data temporarily

Registers that can store any type of data or intermediate result during program execution.