Descriptor Length

Versal ACAP Technical Reference Manual (AM011)

Document ID
AM011
Release Date
2022-04-26
Revision
1.4 English

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.

Table 1. GEM Descriptor Length
Word Length Bit Length 64-bit Addressing (AXI Master 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