Page 28 - The Ultimate Palm Robot

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Bots /The Ultimate Palm Robot/ Mukhar & Johnson / 222880-6 / Chapter 1

Chapter 1 Meeting the Palm Robot 11

CPU

We keep saying that the Palm is the brain of the robot, but really, the brain is
the CPU that powers the Palm. As we mentioned earlier, the CPU inside the
vast majority of Palm OS devices is Motorola’s DragonBall processor. It’s not
particularly fast or otherwise advanced, but the DragonBall is a CPU very
much like the one that powers your desktop computer. It does all the same
functions, input, processing, and output, just like a desktop computer.
This is important for us because the computer programs that drive the ro-
bot will need to be processed by this CPU. Dave’s digital toothbrush wouldn’t
work well because it doesn’t need a full-featured CPU. The Palm, on the other
hand, does. While embedded processors inside most digital devices tend to
have very little functionality (to save cost), or are quite specialized to cater to
the limited needs of the device, the Palm’s DragonBall is a general-purpose
processor, thus more suited for use in a robot that needs to be programmed for
many different tasks. As an added bonus, most Palms come with plenty of
memory for the programs we will put onto the PDA.

Communication
The brain of our robot needs some way to communicate with the electronics
and motors that power the robot. PDAs are perfect for this. Although PDAs
can function without a PC (and certainly, some people own PDAs without
owning a PC), they are designed to be able to connect to a PC. Why? Most
PDAs are considered to be companion products to the PC, sharing and syn-
chronizing data with the programs you already have on the desktop. Plus, the
PC is a convenient conduit for installing new programs on your PDA. This
communication for the Palm originally occurred with a standard serial cable
(although it had a special connection on the Palm end). The communication
protocol was well documented so that developers could write their own pro-
grams that transferred data to and from the PC.
It is this communication channel that makes the Palm perfect for control-
ling our robot. As we will see in later chapters, the controller for the robot
communicates with the PDA through a serial cable, which attaches to the
PDA’s standard synchronization port (see Figure 1-1). Readings from the

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