Re: [avr-libc-dev] [bug #37901] CRC-CCITT calculation incorrect

[Erik Walthinsen]

On 12/11/2012 07:50 AM, Weddington, Eric wrote:
> We need to support the xmega users better. If they're getting easily confused, 
> then we need to help.

It took me a while to discover that the Xmega "CCITT" wasn't the same as 
the avr-libc function, and yes, the difference between _xmodem and 
_ccitt isn't all that well described (esp if/since they're actually 
inverse of each other polynomial-wise).  Plenty of trouble finding the 
right Python code to insert into my passive bus sniffer too.  Not 
looking forward to figuring out CRC-32 re: the NVM, the CRC module, and 
python.  That *should* be easier since they claim it's 802.3 and afaik 
crc32 is quite a bit more standardized, but...

The key for me was finding this page:

<http://www.lammertbies.nl/comm/info/crc-calculation.html>