Special Considerations for XPIO Usage - 2024.2 English - UG909

Vivado Design Suite User Guide: Dynamic Function eXchange (UG909)

Document ID
UG909
Release Date
2024-12-13
Version
2024.2 English
When including XPIO within a reconfigurable partition, the reconfigurable module with the greatest amount of usage must be included in the parent configuration. Any XPIO sites that remain unused in that initial configuration are tied to ground to meet silicon requirements. These tie-offs are considered static and remain for subsequent configurations, which means these sites are unavailable for RMs in child configurations. The Vivado tools automatically insert PROHIBIT constraints on unusable sites. Attempts to assign I/Os to these sites result in an error. For example:
ERROR: [DRC HDPR-29] Reconfigurable logic illegally placed: Reconfigurable logic 'design_top/pl_top/instance_1' is placed at site 'IOB_X52Y0' outside reconfigurable Pblock 'my_dynamic_pblock'.

The recommended strategy is to build the worst case (greatest usage), which is declared in the parent configuration so all subsequent RMs have equal or lesser usage. In hardware, partial images can be delivered in any order.