Microcontrollers
Are Everywhere
Used in everything from the simplest lawn-watering controller to highly sophisticated satellite systems, the microcontroller has become ubiquitous and invisible. The average U.S. household has about 60 embedded microcontrollers.1 A 1999 BMW 7-Series has 65 microcontrollers.2 Over 5 billion microcontrollers are added to the mix annually. Although the microcontrollers in PCs are the most visible, they account for just 6% of the microcontroller market.
In
the office, microcontrollers are used in computer keyboards, monitors, printers,
copiers, fax machines, and telephone-systems to name a few. In your home,
microcontrollers are used in microwave ovens, washers and dryers, security
systems, lawn sprinkler-station controllers, and music/video entertainment
components.
Microcontrollers are complete computer systems on a chip, typically combining an arithmetic logic unit (ALU), memory, timer/counters, serial port, input/output ports (I/O), and a clock oscillator.
Microcontrollers are used in applications requiring repetitive operations, such as running the traffic light at an intersection. In this application, the microcontroller's sole function is to turn lights on and off at predetermined times.
Another
example is a microwave oven. Let's examine how a microcontroller functions while
cooking a bag of popcorn in a microwave oven.
You
open the door and put the bag of popcorn inside. You close the door and push the
button labeled "Popcorn." A few minutes later, a tone announces the
popcorn is done. What happened behind the scenes?
When
you opened the door, the microcontroller sensed the door switch, turned on the
light and disabled the magnetron. The microcontroller continually scans the
keyboard. When you pushed the "Popcorn" button, the microcontroller
confirmed that the door was closed and began to count timing pulses, started the
motor for the turntable, set the power level of the magnetron, and controlled
the display. When the timer reached zero, the microcontroller shut down the
magnetron, stopped the turntable, and signaled you.
This
is a simple example of a microcontroller application. Microcontrollers are
available with extra features such as analog-to-digital converters (ADCs),
pulse-width modulation (PWM), watchdog timers, controller area network (CAN),
and security functions.
Maxim/Dallas
Semiconductor offers four categories of microcontrollers: secure, networking,
mixed signal, and 8051 drop-in compatible.
Secure
Microcontrollers High-speed
8051-compatible microcontrollers designed to resist all levels of threat,
including observation, analysis, and physical attack.
Networking
Microcontrollers Network
compatible 8051 microcontrollers with CAN, Ethernet, RS-232 serial, I2C, 1-Wire®
net, and TINI™ (Tiny InterNet Interface).
Mixed-Signal
Microcontrollers High-speed
8051-compatible microcontrollers with ADC and PWM outputs.
8051
Drop-in Compatible Microcontrollers
High-speed 8051 pin and instruction-set compatible microcontrollers.