丝印代码：18B20；The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user- programmable upper and lower trigger points.

FEATURES  1-Wire Interface Requires Only One Port Pin for Communication  Each Device has a Unique 64-Bit Serial Code Stored in an On-Board ROM  Multidrop Capability Simplifies Distributed Temperature-Sensing Applications  Requires No External Components Can Be Powered from Data Line;