SNLS643C March 2019 – April 2024 DS90UB953A-Q1
PRODUCTION DATA
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 6-3 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. |