1.1 Systems Architecture

Front

CPU

Back

Central Processing Unit

Front

Purpose of the CPU

Back

The purpose of the CPU is to fetch, decode, and execute instructions.

Front

PC

Back

The program counter holds the address of the next instruction to be fetched from memory.

Front

MAR

Back

The memory address register holds the address of the instruction to be fetched from RAM. It can also hold the address of the piece of data to be read or written from RAM.

Front

MDR

Back

The memory data register holds the instruction or piece of data from the RAM. It can also hold a piece of data before it's written to the RAM.

Front

ACC

Back

The accumulator holds the result of any calculations or logic decisions from the ALU.

Front

ALU

Back

The arithmetic logic unit performs arithmetic calculations and logic decisions.

Front

CU

Back

The control unit controls the flow of data around the CPU by sending read and write signals.

Front

Von Neumann Cycle (Shorter version)

Back

Instructions are fetched from memory (RAM), decoded by the control unit, executed, and the cycle is continuous. The program counter is incremented by one.

Front

Embedded System

Back

An embedded system is a smaller system inside of a larger system with a single purpose.