Von Neumann Architecture of Microcontroller

Von Neumann architecture has a single, common memory space where both program instructions and data are stored. There is a single data bus which fetches both instructions and data. Each time the CPU fetches a program instruction it may have to perform one or more read/write operations to data memory space. It must wait until these subsequent operations are complete before it can fetch and decode the next program instruction. The advantage to this architecture lies in its simplicity and economy.

NOTE

On some Von Neumann machines the program can read from and write to CPU registers, including the program counter. This can be dangerous as you can point the PC at memory blocks outside program memory space. Careless PC manipulation can cause errors which require a hard reset.