Microcontrollers

Last time we introduced what microcontrollers can do.
But what is inside a typical microcontroller chip?

Well, it contains:

A central processing unit or CPU which processes instructions. Analogy: A brain instructing an arm how to pick up a cup of coffee. Or reading though a list of groceries and finding them on supermarket shelves in order.

It contains registers - very fast memory which the CPU directly accesses to temporarily store information.

It contains RAM - updateable memory which loses its information on power off. An analogy is a person's brain only needing information for now and discarding it later

ROM - memory which used to store programs and retains it even when the power is off. An analogy is remembering how to drive to work. Your remember that whenever you need the information. Its always there.

A CLOCK which is a square-wave oscillator driven by an external crystal. It is the heartbeat of the microcontroller to step instructions though. The faster the clock, the faster the microcontroller processes instructions.

Contains input/output or I/O lines to interface to the outside world. An analogy is a human ear or mouth.

Some microcontrollers can accept both digital and analogue information in its I/O ports. An analogue input can be used for example to measure a voltage from some other piece of equipment.

Other I/O can include an RS-232 or serial interface, which can talk to a PC.

Next time I will discuss how to select a microcontroller chip for your application.

David, VK3DRB, Melbourne,

Source: Wireless Institute of Australia

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