code: func (m *MotorDriver) sendSpeed(speed int16) {
  	bufOut := new(bytes.Buffer)
  
  	// byte sequence: 0xff, 0x55, id, action, device, port
  	bufOut.Write([]byte{0xff, 0x55, 0x6, 0x0, 0x2, 0xa, m.port})
  	binary.Write(bufOut, binary.LittleEndian, speed)
  	bufOut.Write([]byte{0xa})
  	m.megaPi.writeBytesChannel <- bufOut.Bytes()
  }
docs: // sendSpeed sets the motors speed to the specified value