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crc16 calculation

Posted by clubnet (clubnet), 4 November 2008
I am currently trying to get the crc16 of a hex string in tcl ,

the hex string is as follows 0x00 0x01 0x11 0xFF and then send it to a serial interface

How do i do this in tcl using polynomial 0x8005

The resulting crc checksum should be in two bytes and the result for the above string is 0xE4 and 0x15 which was calculated in C

The c code is as follows can I do the same in tcl

#define CRC16_POLY          0x8005
#define CRC_INIT     0x0

INT16U culCalcCRC(INT8U crcData, INT16U crcReg)
   INT8U i;

   for (i = 0; i < 8; i++) {
       if (((crcReg & 0x8000) >> ^ (crcData & 0x80))
           crcReg = (crcReg << 1) ^ CRC16_POLY;
           crcReg = (crcReg << 1);

       crcData <<= 1;
   return crcReg;

INT16U GenCRC(INT8U *p, INT8U n)
INT8U i;
INT16U checksum = CRC_INIT;  

for(i = 0; i < n; i++)
 checksum = culCalcCRC(*p++, checksum);
       //need to change
       checksum=(checksum<< + i;
return checksum;

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