使用NXP的RC522芯片编写的Mifare_S50的读卡程序，实现了USB的免驱动。-Written Mifare_S50 use NXP RC522 chip card reader procedures, to achieve the USB-free driving.

USB口打印机开启钱箱,里面有两种写法的源代码-USB port on the printer is turned on cash box, there are two ways for writing the source code