Page 123 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

As the name implies, a single-chip computer is an entire computer
system that lies within the confines of an integrated circuit (IC) chip.
The microcontroller existing on the encapsulated sliver of silicon has
features and similarities to our standard personal computer (PC).
Primarily the microcontroller is capable of storing and running a pro-
gram (most important feature). The microcontroller contains a
central processing unit (CPU), random access memory (RAM),
read only memory (ROM), input/output (I/O) lines, serial and
parallel ports, timers, and sometimes other built-in peripherals
like analog-to-digital (A/D) and digital-to-analog (D/A) converters.

Why use a microcontroller?

The microcontroller’s ability to store and run unique programs
makes it extremely versatile. For instance, one can program a micro-
controller to make decisions (perform functions) based on prede-
termined situations (I/O line logic) and sensor readings. Its ability to
perform math and logic functions allows it to mimic sophisticated
logic and electronic circuits. Still other programs can make the
microcontroller behave like a neural or fuzzy logic controller.

The output of the microcontroller can control direct current (DC)
102 motor drives [using DC or pulse-width modulation (PWM)], servo
motor positioning, stepper motors, etc. Programming a robot’s
microcontroller to respond to sensor readings or a communication
link creates an intelligent, responsive robot. Microcontrollers are
responsible for the “intelligence” in most smart devices on the
consumer market and will be the intelligence in our robots.

PIC programming overview

Programming PIC microcontrollers is a three-step process. Before
you can program, however, you need to purchase two items, the
PICBASIC compiler program and the EPIC programmer (a program-
ming carrier board). These two items do not include the PIC micro-
controller chip or its support components. I recommend beginning
with the 16F84 PIC microcontroller because it is a versatile 18-pin
chip with 13 I/O lines and rewritable flash memory. This flash mem-
ory allows you to reprogram the PIC microcontroller chip 1000
times. This is really useful when testing and debugging your pro-
grams and circuits.
The PICBASIC compiler (see Fig. 6.1) runs on a standard PC. The
program may be run in DOS or in an “MS-DOS Prompt” window in
the Windows environment. Hereafter the MS-DOS Prompt window
will be referred to simply as a DOS window. The DOS program will
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Chapter six