Micro-controllers, embedded electronics, and integrated circuits allow considerable design latitude in all types of electronic devices.
Electronic devices are everywhere, and they are getting smaller and smarter each year. The basic electronics found in products like sprinkler timers, VCRs, and electric wristwatches can be traced back to 1948 when the transistor was invented. The beginnings of miniature, compact electronic intelligence really began in 1971 when Intel Corporation integrated a number of transistors to build the first microprocessor. It was the brain of a desktop electronic calculator, and it had over 2000 transistors.
At right is an example of how integrated circuits become more compact, yet more capable.
The microprocessors in today's electronics are usually single-chip integrated circuits mounted directly on a circuit board (embedded). When a microprocessor chip is complete with it's own memory, it is called a micro-controller. Both 'micro' devices are integrated circuits that contain many thousands or even millions of transistors and perform typical computer operations or instructions. When incorporating them in medical devices, we have the choice of using micro-controller chips alone, or combining them with the complex circuitry of another class of programmable logic device called a Field Programmable Gate Array (FPGA). FPGAs can allow great reduction in circuit board size when used in place of circuits that are not easily modeled in a micro-controller.
The information contained in program memory guides the controller through a list of steps and decision points one at a time. These "steps" are the language of the digital world. Today's chips can process each step very quickly, sometimes at the rate of millions of instructions per second.
Speedier micro-controllers allow programmers to write sophisticated software instructions that previous embedded devices would have taken too long to perform. This increase in calculation power has allowed us to engineer products that were not previously possible.
Small physical size sometimes masks the complexity of today's electronics. New technologies have given us more design and engineering latitude. Flex circuits and surface mount electronic parts, smaller more powerful embedded micro-controllers, and programmable logic devices make the possibility of "stuffing 10 pounds of components into a one pound box" a reality.