这是我自己写的一个热水卡管理系统，主要是接收串口中的数据，对读取RFID卡，写数据到RFID卡的操作都 有，初学者可以参考-This is a hot to write my own card management system, mainly to receive the serial data in the RFID card, read, and write data are to the RFID card operation, beginners can refer to