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Definition: microcontroller
A single chip that provides computer processing in everything from appliances to toys to automobiles. There can be dozens of microcontoller units (MCUs) in a vehicle along with many other types of chips.
They Don't Get the Publicity
Because MCUs have 8-, 16- and 32-bit CPUs (rather than 64 bits) and cost only a few dollars, they never get mainstream attention like the latest Intel, Apple and Qualcomm chips do. MCUs are also not built with state-of-the-art manufacturing technology like the chips in smartphones, tablets and computers (see process technology). In addition, MCUs are not the chips users buy to upgrade their PC motherboards. Instead, they are built into products and remain there. See embedded system and automotive systems.
The Microcontroller Chip
Motorola 6801 Microcontroller
They Don't Get Much Smaller
An MCU Behind Everything
Are You Crazy?
They Don't Get the Publicity
Because MCUs have 8-, 16- and 32-bit CPUs (rather than 64 bits) and cost only a few dollars, they never get mainstream attention like the latest Intel, Apple and Qualcomm chips do. MCUs are also not built with state-of-the-art manufacturing technology like the chips in smartphones, tablets and computers (see process technology). In addition, MCUs are not the chips users buy to upgrade their PC motherboards. Instead, they are built into products and remain there. See embedded system and automotive systems.
An MCU contains the CPU for instruction execution, non-volatile storage (flash memory or ROM) for the program, volatile memory (RAM) for processing and input/output control between all components: CPU, storage, memory and the outside world. A clock makes everything go. See CPU, flash memory, ROM, RAM and clock.
Introduced in the late 1970s, the 6801 was a popular MCU. These magnified images show the entire chip (top), most of the 256 bytes of RAM (bottom left) and two bytes at 400x magnification (bottom right). At this magnification, a single byte in today's chips would not be observable.
These 8-bit microcontrollers (PIC brand) from Microchip in Tempe, Arizona are used in myriad applications, cost less than 50 cents in quantity and are much more powerful than the 6801 above. We're not great at predicting technology. In 1949, Popular Mechanics speculated that future computers would only weigh "one and a half tons!"
Today's vehicles can have thousands of microcontrollers, each handling a simple function such as turning a light on to more complicated systems like the ones above.
After taking a tour "inside" the Univac I in the 1950s, imagine someone saying "this entire computer will be no larger than the lead tip of a pencil some day." See UNIVAC I.