TCCR1A = _BV(COM1A1) |  _BV(COM1B1) |  _BV(WGM11);
  TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS11) ; 
  //TCNT1 = 0;  // clear the timer count 

  // Set the value of TOP, which generate 50HZ frequency (20ms per cycle) 
  ICR1 =  40000 - 1;

  // Map the angle value to counter, then set counter, begin count
  unsigned int counter = map(angle, 0, 180, MIN_PULSE_WIDTH/0.0005, MAX_PULSE_WIDTH/0.0005);
  OCR1A = counter;  

最最最核心的代码就是这些啦
我可以把328P 手册 TIME1的设置啥的研究了个遍，才写出这段代码的