Training, Open Source computer languages
PerlPHPPythonMySQLApache / TomcatTclRubyJavaC and C++LinuxCSS 
Search for:
Home Accessibility Courses Diary The Mouth Forum Resources Site Map About Us Contact
 
For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
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;
       else
           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
i=(checksum>>&0xff;
       checksum=(checksum<< + i;
return checksum;
}





This page is a thread posted to the opentalk forum at www.opentalk.org.uk and archived here for reference. To jump to the archive index please follow this link.

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2024: Well House Manor • 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01144 1225 708225 • FAX: 01144 1225 793803 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho