A single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers.
Microcontrollers come in all sizes and architectures, with the smaller, commodity chips costing as little as 50 cents in quantities of 10,000.
This diagram shows the components of a Motorola 6801. Introduced in 1978, it was one of the first semiconductor products to claim the "computer on a chip" moniker.
These highly magnified images are of the actual 6801 chip. The middle picture shows all 256 bytes of RAM memory with barely six bits revealed at the bottom (400x magnification).
These PICmicro chips from Microchip (www.microchip.com) are the world's smallest microcontrollers. Used in a myriad of applications, such chips can sell for as little as 50 cents in quantities of 10,000 (2007 dollars).
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