copper230230
Newbie level 6
Dear Sirs,
When I study the USB spec, it said that the CRC polynomial of token was:
G(x) = X^5 + X^2+1
When the host send message with crc to device, then device use this CRC to
check these data. If no error occured, the residual was X^5+X^3+X^2.
I also found some document, but I can't understand what it meant at the item
3 at page 2.
( www.usb.org/developers/whitepapers/crcdes.pdf )
Why the residual will always be a constant?
If someone can kindly tell me the math inside this constant which CRC
residual.
Thanks!!
When I study the USB spec, it said that the CRC polynomial of token was:
G(x) = X^5 + X^2+1
When the host send message with crc to device, then device use this CRC to
check these data. If no error occured, the residual was X^5+X^3+X^2.
I also found some document, but I can't understand what it meant at the item
3 at page 2.
( www.usb.org/developers/whitepapers/crcdes.pdf )
Why the residual will always be a constant?
If someone can kindly tell me the math inside this constant which CRC
residual.
Thanks!!