The only difference between a micro-controller and a micro-processor is, micro-processors do not have RAM/ROM, which need to be added externally. Most of the embedded devices/systems today utilize micro controllers that have a CPU and fixed amount of RAM/ROM.

The following figure depicts the typical architecture components of a simple embedded device:

The components of an Embedded system are as follows:

• Hardware: This includes the chipsets, processors such as ARM (most widely deployed), MIPS, Ambarella, Axis CRIS, Atmel AVR, Intel 8051, or Motorola power microcontrollers.
• Operating System: The majority of the embedded systems are Linux-based and those are real-time operating systems (RTOS) customized for the purpose of the device. There might be some questions raised in the tester's mind, such as, what is the difference between the operating system and the firmware? Firmware allows device manufacturers to use general purpose, programmable chips instead of custom-purpose hardware.
• Application software: This is the custom application to control the device and its features; mostly a web application to configure or update the device.