>>Thanks for noticing. I had already tried with a zero offset with no luck. If it helps here is the original C code provided by the manufacturer.
>>
>>//
>>// CRC Calculation & Checking routines for Kingfisher Protocol
>>//
>>unsigned int kf_crc_calc(BYTE *string, int charnum)
>>{
>>int i, j;
>>int c, crc = 0;
>>for (i=0; i<charnum; i++)
>>{ c = string[i] & 0xff;
>>for (j=0; j<8; j++)
>>{ if (crc & 0x8000)
>>{ crc <<= 1;
>>crc += (((c <<= 1) & 0x100) != 0);
>>crc ^= 0x1021;
>>}
>>else
>>{ crc <<= 1;
>>crc += (((c <<= 1) & 0x100) != 0);
>>}
>>}
>>}
>>return(crc);
>>}
>>int kf_crc_check(BYTE *string, int charnum)
>>{
>>unsigned int crc1 = kf_crc_calc(string, charnum);
>>unsigned int crc2 = (int)string[charnum] * 256 + (int)string[charnum+1];
>>if (crc1 == crc2) return(0);
>>else return(1);
>>}
>>void kf_crc_append(BYTE *string, int charnum)
>>{
>>unsigned int crc = kf_crc_calc(string, charnum);
>>string[charnum] = crc / 256;
>>string[charnum + 1] = crc % 256;
>>}
>>>
>
>Jim,
>
>I have converted kf_crc_calc()
>
>I cannot really test it since I have no sample (string, output expected)
>
>
> class test2
> {
> static void Main()
> {
> }
>
> static uint kf_crc_calc(string s, int charnum)
> {
> int i, j;
> uint c, crc = 0;
>
> for (i = -1; ++i < charnum; )
> {
> c = (uint)s[i] & 0xffu;
>
> for (j = 0; j < 8; j++)
> {
> c <<= 1;
>
> if ((crc & 0x8000u) != 0)
> {
> crc <<= 1;
> if ((c & 0x100u) > 0)
> crc++;
> crc ^= 0x1021u;
> }
> else
> {
> crc <<= 1;
> if ((c & 0x100u) > 0)
> crc++;
> }
>
> }
> }
>
> return crc;
>
> }
> }
>Thanks Gregory,
the string 00 08 FF 00 01 22 should return the crc AB 7C . When I put this string into the VB method the CRC AB 7C is returned, but when I put it in the C# method I get back garbage. I think it must have something to do with the way the string is processed. Do you know if the primative data types are the same in VB as in C#? When I run the string through the C# method I get back a very large number even though it should only be 2 bytes.
