10 dim x
  20 dim led as pin pp7 for analog output
  30 while 1 do
  40   for x = 0 to 5000
  50     let led = x
  60     sleep 500 us
  70   next
  80   for x = 5000 to 0 step -1
  90     let led = x
 100     sleep 500 us
 110   next
 120 endwhile