SNLS696A April 2021 – May 2021 TSER953
A long packet consists of three elements: a 32-bit packet header (PH), an application-specific data payload with a variable number of 8-bit data words, and a 16-bit packet footer (PF). The packet header is further composed of three elements: an 8-bit data identifier, a 16-bit word count field, and an 8-bit ECC. The packet footer only has one element—a 16-bit checksum. Figure 7-3 shows the structure of a long packet.
|PACKET PART||FIELD NAME||SIZE (BIT)||DESCRIPTION|
|Header||VC / Data ID||8||Contains the virtual channel identifier and the data-type information.|
|Word Count||16||Number of data words in the packet data. A word is 8 bits.|
|ECC||8||ECC for data ID and WC field. Allows 1-bit error recovery and 2-bit error detection.|
|Data||Data||WC × 8||Application-specific payload (WC words of 8 bits).|
|Footer||Checksum||16||16-bit cyclic redundancy check (CRC) for packet data.|