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.