Von Neumann Architecture

What is the Von Neumann Architecture?

It is a computer design where:

Data and programs are stored in the same memory.
The processor can access the instructions and data in the main memory as required to execute the program. It does this by using dedicated connections called buses:
- an address bus is used to identify the addressed location
- a data bus is used to transfer the contents to/from that location
This means that the same address and data buses are used in the process of transferring instructions and data between main memory and the processor. A third bus, the control bus, is used to synchronise and control operations.

Key parts:

CPU component or register	Definition
	Stores the address of the next instruction to be fetched from memory. Increments during each fetch-execute cycle.
CU (Control Unit)
	Stores the address of the data to be fetched from or the address where the data is to be stored.
	Performs mathematical calculations and logical operations.

CPU component or register	Definition
Program Counter // PC	Stores the address of the next instruction to be fetched from memory. Increments during each fetch-execute cycle.
CU (Control Unit)	(Sends signals to) synchronise / control / coordinates the processor/hardware/F-E cycle/processes/flow of data // decodes instructions (in CIR) // runs F-E cycle
Memory Address Register // MAR	Stores the address of the data to be fetched from or the address where the data is to be stored.
Arithmetic Logic Unit // ALU	Performs mathematical calculations and logical operations.