MODBUS RTU协议的仪表通信时需要进行CRC校验，单片机可以用此程序生成CRC校验码，多项式是0xA001 所用单片机为STC15系列单片机，不过CRC生成过程很简单，通用的51单片机都可以生成(MODBUS RTU protocol instrument communication needs CRC verification, SCM can use this procedure to generate CRC checksum, the polynomial is 0xA001