Embedded Systems (CIE IGCSE Computer Science)

• An embedded system is a computer systems with a either one function or limited specific functions built within a larger mechanical device
• Its purpose is to control the device and allow a user to interact with it
• It runs on firmware and does not have additional peripherals
• An embedded system is different to a general purpose computer system like a laptop or desktop computer which can be used to perform many different tasks
• The vast majority of microprocessors manufactured are for use as embedded systems
• Some embedded systems are microcontrollers meaning they are part of an integrated circuit with built in memory
  
  

Type of embedded system	Description
Microcontrollers	Integrated circuit containing a CPU and memory (RAM or ROM) built in to the same chip
Microprocessor	Integrated circuit containing only a CPU on the chip RAM , ROM , peripherals need to be added

• The microprocessor used in an embedded system is often custom designed
• Embedded systems often have firmware which is software built into the system which cannot be reprogrammed by the user. The software may be able to be updated e.g. GPS software in a car navigation system
• Embedded systems usually have some form of analog or digital input

Diagram of an embedded system

Embedded system	Possible input devices	Possible Output
Digital clock	Buttons to set the time/mode/alarm	Screen showing the time Alarm
Traffic Lights	Pedestrian button Timer Movement sensor	Lights
Lighting system	Movement sensor	Lights
Security system	Keypad to enter alarm code Camera Movement sensor	Alarm
Vending machine	Keypad to make choice	Actuator controlling movement of choice
Central Heating system	Keypad to set temperature Temperature sensor	Heat

• There are many advantages of embedded systems
  • low power consumption
  • small physical size
  • low cost to manufacturer
  • they can be controlled remotely
  • can operate in real time and respond to inputs very quickly