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1、概述

CRC16循环冗余校验常用在MODBUS协议中，用于校验报文的完整性。CRC16校验值为uint16_t 无符号整形2字节，在MODBUS协议中，低检验字节在前，高校验字节在后，比如校验结果crc16=0x1788，则MODBUS中的校验顺序为 ...0x88 0x17。

以下为自己写的linux C 代码，可以直接用。

2、C程序

/*******************************************************************************_____ ___ ____  ___   _____    _             _   _             | ____|_ _|  _ \|_ _| |_   _|__(_)_ __   __ _| | | |_   _  __ _ |  _|  | || |_) || |    | |/ __| | '_ \ / _` | |_| | | | |/ _` || |___ | ||  _ < | |    | |\__ \ | | | | (_| |  _  | |_| | (_| ||_____|___|_| \_\___|   |_||___/_|_| |_|\__, |_| |_|\__,_|\__,_|  * File Name          : main.c  * Description        : This file provides code for crc16 caculation in linuxc.  * Author             : jackwang by jiawang16@foxmail.com  * Date               : 2018-07-15*******************************************************************************//*! -------------------------------------------------------------------------- *//*! Include headers */#include 
   
    #include 
    
     #include 
     
      /*! -------------------------------------------------------------------------- *//*! Private function declarations */static unsigned char Char2Int(char chr,bool *isOK);/*! convert char to int type*/static unsigned char HexStr2Int(char *str, bool *isOK);/*!convert hexstr to int*//*! caculate crc16 of buff-input:arr_buff and length: len */static unsigned short GenerateCRC16(unsigned char *arr_buff, unsigned short len);/*! -------------------------------------------------------------------------- *//*! main function defination */int main(int argc, char* argv[]){  /*! variable define */  int ret = 0;  int numByte = argc;   unsigned char bccVal = 0x00;  char inPutbuff[10];  unsigned char databuff[1000];  unsigned short buffsize = 0;  unsigned short crcVal;  bool isOK;  int Nibb;    if(argc == 1){    printf("[note]  no params to caculate, please input hex string,                                            splite by space!\r\n");  }  else{    printf("[note]  input %d byte: ",numByte-1);    for(int i = 1; i < numByte; i++){      printf("%s ",argv[i]);    }    printf("\r\n");        for(int i = 1; i < numByte; i++){      memcpy(inPutbuff,argv[i],2);      Nibb = HexStr2Int(inPutbuff,&isOK);            if(isOK){        databuff[i-1] = Nibb;        buffsize++;      }    }        crcVal = GenerateCRC16(databuff,buffsize);    printf("[note]  crc16 value: 0x%04X\r\n",crcVal);  }  return 0;}/*! -------------------------------------------------------------------------- *//*! Private function definations *//*! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */static unsigned char Char2Int(char chr,bool *isOK){  unsigned char nibb1;  if(chr >= '0' && chr <= '9'){ nibb1 = chr - '0'; *isOK = true;}  else if(chr >= 'a' && chr <= 'f'){ nibb1 = chr - 'a' + 10; *isOK = true;}  else if(chr >= 'A' && chr <= 'F'){ nibb1 = chr -'A' + 10; *isOK = true; }  else{  printf("[error]  invalid hex str input: %c \r\n",chr); *isOK = false; }  return nibb1;}/*! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */static unsigned char HexStr2Int(char *str, bool *isOK){  unsigned char nibb1,nibb2;  bool isOK1,isOK2;  nibb1 = Char2Int(*str, &isOK1);  nibb2 = Char2Int(*(str+1),&isOK2);    if(isOK1 && isOK2){    *isOK = true;    return nibb1*16 + nibb2;  }  else{    *isOK = false;    return 0;  }} /*! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */static unsigned short GenerateCRC16(unsigned char *arr_buff, unsigned short len){    unsigned short crc=0xFFFF;    unsigned char i, j;    for ( j=0; j < len;j++){        crc=crc ^*arr_buff++;        for ( i=0; i<8; i++) {            if( ( crc&0x0001) >0){                crc=crc>>1;                crc=crc^ 0xa001;            }            else{ crc=crc>>1;}        }    }    return crc;}
     
    
   

3、编译

~$ gcc main.c -o getcrc16

4、使用

~$ ./getcrc16 01 03 00 04 00 04~$ [note]  input 6 byte: 01 03 00 04 00 04~$ [note]  crc16 value: 0xC805

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