SHT20温湿度传感器驱动程序，经修改，在原子开发板上调试成功。可准确读取温度和湿度。编译环境为Keil MDK ARM 5.14((Modified SHT20 driver source code of Huaxiong electronic. Successed run in atomic development board, can read the temperature and humidity. Compiled by Keil MDK ARM 5.14.))