下面的程序为读出RC500和MIFARE卡的序列号，选择一个卡，将该卡的20块初始化成值块且备份到21块最后使该卡进入HALT状态，且驱动2kHz蜂鸣器响200次。-The following procedure for reading out the RC500 and MIFARE card serial number, select a card, the card 20 is initialized as the value of block 21 and back up to the end of the card to enter the HALT state, and drive 200 ring buzzer 2kHz times.