Definitions: “Embedded Systems are devices which are used to control, monitor or assist the operation of an equipment, machinery or plant”. The term “control” defines the main function of Embedded System because their purpose is to control an aspect of a physical system such as pressure, temperature and so on. Also the term “monitor” defines the progress of activities.
An embedded device can range from a relatively simple product for ex. a toaster to complex mission critical applications such as those used in avionics. A typical embedded device will have both hardware and software components. The hardware could be micro components such as embedded microprocessor or microcontroller. Microcontroller is relatively small, has a onchip memory, an I/O controller and other supported modules to do processing and controlling tasks. The software consists of applications that perform dedicated tasks and may run on Real time operating system which will be explained later in this unit.
Embedded System may be either an independent system or a part of a large system. It is specialized computer system but not a general purpose workstation like a desktop or a computer. Such kind of systems is housed on a single microprocessor board with programs which are stored in ROM (Read Only Memory). Embedded system is usually a compact, portable and mass produced electronic devices. In the early days, embedded systems were designed using microprocessors like 8085. But nowadays, we are using a wide range of processors from other manufacturers.
Almost all modern electronic devices use some sort of embedded system technology inside them and we always come across such devices: DVD players, air conditioners, printers, attendance machines, hand phone, digital camera, ATM machines and many more.