I just wired one of these up last night. It has a _lot_ of features to make it more complicated, but you don't have to use all them. Also, I think this document is more helpful than the one you linked to:
http://www.zilog.com/docs/devtools/ps0284.pdfFor the simplest implementation, see the attached circuit diagram and the code:
/* ZILOG - Motion Activated LED */
int motionDetect = 7;
int led = 13;
void setup()
{
pinMode( motionDetect, INPUT );
pinMode( led, OUTPUT );
delay(100);
}
void loop()
{
if ( digitalRead( motionDetect ) )
{
/* turn the LED on */
digitalWrite( led, LOW );
}
else
{
/* turn the LED off */
digitalWrite( led, HIGH );
}
delay(25);
}
Hope that helps!