URL:
<http://savannah.nongnu.org/bugs/?45067>
Summary: inconsistency & errors in crc.h documentation
Project: AVR C Runtime Library
Submitted by: None
Submitted on: Sun 10 May 2015 05:59:16 PM UTC
Category: Documentation
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Documentation
Status: None
Percent Complete: 0%
Assigned to: None
Originator Email: ralphdoncas...@gmail.com
Open/Closed: Open
Discussion Lock: Any
Release: 1.8.0
Fixed Release: None
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Details:
>From http://www.nongnu.org/avr-libc/user-manual/group__util__crc.html:
"Optimized CRC-XMODEM calculation.
x^16 + x^12 + x^5 + 1 (0x1021)"
The hex representation of the poly is correct, but doesn't match the long
form, which should be:
x^16 + x^15 + x^5 + 1
Other parts of the docs give the reversed poly in hex instead of the actual
poly:
"Optimized Dallas (now Maxim) iButton 8-bit CRC calculation.
Polynomial: x^8 + x^5 + x^4 + 1 (0x8C)"
It would be better to describe them the way pycrc does, with the actual poly
used and whether or not the crc reflects (reverses) the bits.
https://www.tty1.net/pycrc/crc-models_en.html
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