ABSTRACT
An embedded system is a special-purpose system that embeds a computer and is designed to perform one or a few predened tasks, usually with very specic requirements. That is, the computer system is completely encapsulated by the device it controls. For instance, a trafc light controller is a system that is designed to perform that single function. The heart of the system is the processor (computer) embedded in it. In contrast, our desktop systems are personal computers that perform general-purpose computation tasks. Since embedded processors are dedicated to specic tasks, their design can be optimized to reduce the size and cost of the system. They are often mass produced, thus multiplying the cost savings. Almost all systems we use in our daily lives today embed computers. Some of the examples are the following:
Probably the rst mass-produced embedded processor was the Autonetics D-17 guidance computer built in 1961 for the Minuteman missile. It was built from discrete transistor logic devices with a hard disk main memory. In 1966, the D-17 was replaced by a new design that was the rst highvolume use of integrated circuits (ICs). In 1978, National Engineering Manufacturers Association released the standard for a programmable microcontroller. The denition included single-board computers, numerical controllers, and sequential controllers that perform event-based instructions.
