The length of a descriptor entry depends on the interface (AXI or external FIFO interface) and if the timestamp feature is enabled. Every buffer descriptor entry has the same number of words for a given mode. This functionality applies to RX and TX descriptors.
| Word Length | Bit Length | 64-bit Addressing (AXI Interface) | 32-bit Addressing (External FIFO Interface) | Timestamp Capture |
|---|---|---|---|---|
| 2 words | 64 | ~ | Yes | ~ |
| 4 words | 128 | Yes | ~ | ~ |
| 4 words | 128 | ~ | Yes | Yes |
| 6 words | 192 | Yes | ~ | Yes |