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CRC5 for use in Start-of-Frame (SOF) token packets
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Topic: CRC5 for use in Start-of-Frame (SOF) token packets (Read 9037 times)
herbertp
Member
Posts: 1
CRC5 for use in Start-of-Frame (SOF) token packets
«
on:
June 03, 2015, 05:47:23 pm »
In the CRC5 function found in usb_crc.c, that is available on this website, which CRC5 does it generate.
http://en.wikipedia.org/wiki/Polynomial_representations_of_cyclic_redundancy_checks
I was stepping through the code on a debugger when I noticed that the poly5 variable didn't match CRC5-USB.
It looked like it was CRC5-EPC instead.
Please help
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Jan Axelson
Administrator
Frequent Contributor
Posts: 3033
Re: CRC5 for use in Start-of-Frame (SOF) token packets
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Reply #1 on:
June 03, 2015, 09:06:34 pm »
The source that file references:
http://www.usb.org/developers/whitepapers/crcdes.pdf
refers to x5 + x2 + x0, which would be CRC5-USB.
Also see 8.3.5 in the USB 2.0 spec.
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CRC5 for use in Start-of-Frame (SOF) token packets