AXI ID Compression - 1.0 English

Versal ACAP Programmable Network on Chip and Integrated Memory Controller LogiCORE IP Product Guide (PG313)

Document ID
PG313
Release Date
2022-12-14
Version
1.0 English

The NoC request packet from the NMU carries the triple {Source ID, AXI-ID, Tag} for read requests and {Source ID, AXI-ID} for write requests. Non-DDR memory controller NSUs send a compressed AXI-ID to the downstream AXI slave. There are two programmable compression modes:

  • A 2-bit compressed AXI-ID is created by choosing any two bits of the {Source ID, AXI-ID}. The bit selection is programmed as part of the NSU configuration..
  • A 2-bit fixed value determined by a configuration register. This mode effectively forces read and write requests to remain in order.

By default the NSU will select the least significant two bits of the request AXI-ID as the compressed ID. DDR memory controller NSUs do not compress the AXI-ID.