Build Your Own Combat Robot

Chapter 12: Robot Brains 263
space in which programs can fit. The concept is different than how regular PCs refer
to memory. In Table 12-1, all the values shown are in kilobytes, except for the
Basic Stamp 1—which has only 256 bytes of programming space. To some people,
this doesn’t sound like a lot, but 256 bytes represents quite a lot of programming
space in a microcontroller.
Some microcontrollers execute one command at a time, and some can execute
multiple commands at the same time. For some applications, such as controlling
16 different R/C servos in an animatronics movie puppet, being able to execute
multiple commands simultaneously, or multitasking, can be helpful.
The microcontroller used in your bot can be either a small circuit board that
connectors plug into, or a large integrated circuit. One of the common sizes for the
microcontrollers is the 24-pin dual inline pin (DIP) socket. Basic Stamp started
with this size, and several different companies have made Basic Stamp variants
that are pin-for-pin, identical.
Unfortunately, no one programming language can be used to program all
microcontrollers. Many of the languages are based on the popular Basic programming
language or the C programming language. If you know how to program in
either of these languages, you should be able to program one of these
microcontrollers.
Basic and C are called high-level languages, and they are easy to learn and understand
when compared to using the assembly language. A compiler compiles (or
converts) the high-level language into a low level language that the
microcontroller actually understands. For example, here is a simple instruction
written in Basic that is easy to understand:
X = Y + Z
If this is written in assembly language, it would look like this:
MOVF Y,0
ADDWF Z,0
MOVWF X,0
This isn’t easy to understand. The preceding assembly language example will
be different from microcontroller to microcontroller, but the Basic language will be
the same regardless of the microcontroller.
When you get started in the world of microcontroller programming—or, as the
electrical engineers like to call it, programming embedded controllers—pick something
you like and stick with it until you master it. Interfacing a microcontroller
with the outside world is the same regardless of which microcontroller you choose.
Master the interfacing techniques on one microcontroller before you move on to
another type of microcontroller.