Return all of the addresses table of DS18B20 on one-wire. 如果没有执行过setup(pin),则会自动对引脚9(GPIO2)进行单总线模式初始化。<br/>
Return a table contain all of the addresses of DS18B20 on one-wire. If the setup(pin) function not executed, the pin 9(GPIO2) will be initialized as one-wire mode automatically. <br/>
addr: string, the address of DS18B20. It will select the first address which be found when this parameter is nil.<br/>
unit: integer, unit conversion. Only Constant is acceptable, such as C(Celsius),F(Fahrenheit) and K(Kelvin). If this parameter is nil, the constant C(Celsius) will be selected automatically. <br/>
addr: string, the address of DS18B20. It will select the first address which be found when this parameter is nil.<br/>
unit: integer, unit conversion. Only Constant is acceptable, such as C(Celsius),F(Fahrenheit) and K(Kelvin). If this parameter is nil, the constant C(Celsius) will be selected automatically. <br/>