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