说明：  循环冗余码CRC检验技术广泛应用于测控及通信领域。CRC计算可以靠专用的硬件来实现，但是对于低成本的微控制器系统，在没有硬件支持下实现CRC检验，关键的问题就是如何通过软件来完成CRC计算，也就是CRC算法的问题。
(CRC cyclic redundancy code inspection techniques widely used in the field of control and communication. CRC calculation can rely on proprietary hardware to achieve, but low-cost micro-controller system, In the absence of hardware support under CRC test, the key issue is how to accomplish through software CRC calculation, CRC algorithm is the problem.)