code: func (p *PCA9685Driver) PwmWrite(pin string, val byte) (err error) {
  	i, err := strconv.Atoi(pin)
  	if err != nil {
  		return
  	}
  	v := gobot.ToScale(gobot.FromScale(float64(val), 0, 255), 0, 4096)
  	return p.SetPWM(i, 0, uint16(v))
  }
docs: // PwmWrite writes a PWM signal to the specified channel aka "pin".
  // Value values are from 0-255, to conform to the PwmWriter interface.
  // If you need finer control, please look at SetPWM().
  //