SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
A long packet is identified by data types 0x10 to 0x37. A long packet consists of three elements:
The packet header is further composed of three elements:
The packet footer has one element, a 16-bit checksum.
Figure 10-17 and Table 10-14 show the structure of a long packet.
Packet Part | Field Name | Size (Bits) | Description |
---|---|---|---|
Header | Data ID | 8 | Contains the virtual channel identifier for data and the data-type for the application specific payload data |
Word count | 16 | Number of 8-bit data words in the Data Payload between the end of the Packet Header and the start of the Packet Footer. Neither the Packet Header nor the Packet Footer are included in the Word Count. | |
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 CRC for packet data |
There are no restrictions on the size of the packet data, but each data format can impose additional restrictions on the length of the payload data (for example, a multiple of 4 bytes).