rfid new code

代码说明：

说明：  In the data management system a significant role of the Data link layer is to convert the unreliable physical link between reader and tag into a reliable link. Therefore, the RFID system employs the Cyclic Redundancy Check (CRC) as an error detection scheme. In addition for reader to communicate with the multiple tags, an anti-collision technique is required. The technique is to coordinate the communication between the reader and the tags. The common deterministic anti-collision techniques are based on the Tree algorithm such as the Binary Tree and the Query Tree algorithms.