[email protected] (ALuPin) wrote in message news:<[email protected] com>...
> > The second way is to include the
> > received CRC in the calculation for the check CRC. If you do this, the
> > result is the magic number (assuming the checker was initialized with
> > all 1's).
>
> Is this magic number (residual) given by all CRCs?
> I have experienced that the USB CRC5/CRC16 have residuals which are
> for all correct calculations the same. But what about other CRCs?

Yes, all CRC's produce a residual - it is a function of the following items:

* The CRC polynomial being used (CRC-16 vs. CRC-CCITT vs. CRC-32, etc)
* The initial value (sometimes all 1's, but not always)
* Bit and byte ordering (application dependant)
* Bit inversion (application dependant: sometimes XOR with all 1's)


Have fun,

Marc