双模式USB接口芯片CH375在温湿度测记仪中的应用

Design of Double-mode USB Interface of Temperature Humidity Measuring Apparatus

将USB总线接口芯片CH375应用于温湿度测记仪中,使该仪器既可以工作在设备模式下,与计算机直接进行通讯(包括温湿度数据的上传和仪器基本参数的设置),也可以工作在主机模式下,读写U盘,通过U盘作为中介实现数据的传输,使温湿度测记仪不用离开测试现场就可以和PC机进行数据通讯,方便了用户的使用。测记仪使用双USB插座,由单片机智能判断连接的设备类型,并自动切换至对应的工作模式下。

The USB bus interface chip CH375 is applied in temperature humidity measuring apparatus, which makes the measuring apparatus can work not only in USB-DEVICE mode to communicate directly with computer, but also in USB-HOST mode to read-write flash memory to transmit data（include temperature and humidity data uploading and the fundamental parameters of instrument downloading）, which makes it work always at testing and measurement locale, so it provides more convenience for users. It has two USB plug seats, which can be distinguished intelligently device type connected with it and exchanges automatically the corresponding work mode by the Single Chip Micyoco.