Page 28 - PDA Robotics Using Your Personal Digital Assistant to Control Your Robot

PDA 01 5/30/03 9:09 AM Page 5
Chapter 1 / Anatomy of a Personal Digital Assistant (PDA)
Graffiti writing area: The area where you write letters and num-
•
bers using the Graffiti alphabet.
• Scroll buttons: Display text and other information that extends
beyond the area of the handheld screen. Pressing the lower scroll
button scrolls down to view information below the viewing area,
and pressing the upper scroll button scrolls up to view the infor-
mation above the viewing area.
• Application buttons: Activate the individual handheld applica-
tions that correspond to the icons on the buttons: Date Book,
Address Book, To Do List, and Note Pad. These buttons can be
reassigned to activate any application on your handheld.

• Tip: If your handheld is turned off, pressing any application
button activates the handheld and opens the corresponding
application.

Beneath the Cover

PDAs are miniature versions of typical desktop systems; however,
space and power consumption constraints have limited the processing
power, storage space, and memory available. (This may not be true for
long!) These constraints have led to very innovative designs.

Beneath the cover of each PDA is a microprocessor, which is the
“brain” of the unit. All information flows in or out of it. Attached to
the microprocessor are a number of peripheral devices such as the
touch screen, IR port, speaker, and memory modules.

Two popular PDA microprocessors are the Intel StrongARM (Figure
1.3) and the Motorola DragonBall. The Intel microprocessor is typical-
ly used in devices running Windows CE, and the Motorola is used
with devices running the Palm OS operating system. These processors
will be described in more detail below.
ARM was established in November 1990 as Advanced RISC Machines
Ltd. In 2001, more than 538 million Reduced Instruction Set
Computing (RISC) microprocessors were shipped, 74.6 percent of
which were based on the ARM microprocessor architecture. ARM
licenses its intellectual property (IP) to a network of partners, which
includes some of the world’s leading semiconductor and system com-
panies, including 19 out of the top 20 semiconductor vendors world-

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