说明：Modbus等协议中需要CRC校验码，这里是一个dsPIC33F芯片的CRC校验码产生器代码，PIC公司给出的，拿来用就是了。当然您可看看这代码究竟是什么样的一个算法过程。-Note: Modbus protocol, such as the need to check code CRC, there is a CRC checksum dsPIC33F chip code code generator, PIC given by the company and used with就是了. Of course you can take a look at this code and what exactly is the process of an algorithm.