// Control the movement of a RC servo, by steps

#define PIN     0
#define STEP    20

main()
{
   int    angle;

   loop {
      for(angle=0; angle <= 180; angle+=STEP) {
         writei('d', angle, 100);
         servo(PIN, angle);
      }
      for(angle=180-STEP; angle >= STEP; angle-=STEP) {
         writei('d', angle, 100);
         servo(PIN, angle);
      }
   }
}