Editing System Management Bus (section)

====Packet Error Checking====
SMBus 1.1 and later define optional '''Packet Error Checking''' ('''PEC'''). In that mode, a PEC (packet error code) byte is appended at the end of each transaction. The byte is calculated as [[CRC-8]] [[checksum]], calculated over the entire message including the address and read/write bit. The polynomial used is x<sup>8</sup>+x<sup>2</sup>+x+1 (the CRC-8-[[Asynchronous Transfer Mode|ATM]] [[CRC-based framing|HEC]] algorithm, initialized to zero).<ref>{{cite web|url=http://sbs-forum.org/marcom/winter01/Designing%20with%20SMBus%202.pdf|title=Designing with SMBus 2.0|website=Sbs-forum.org|access-date=27 October 2017}}</ref><ref>{{cite web|url=http://www.smbus.org/faq/crc8Applet.htm|title=CRC-8 Calculator|website=Smbus.org|access-date=27 October 2017}}</ref><ref>{{cite web|url=http://www.picbasic.co.uk/forum/showthread.php?t=6231|title=CRC-8 for SMBus|website=Picbasic.co.uk|access-date=27 October 2017}}</ref>