It is recommended, and in some cases required, to keep components with dedicated connections in the same partition of the design. Having dedicated connections span the boundary of an OOC module can cause reduced performance and/or implementation errors. The following is a list of components with dedicated connections.
- IOLOGIC and IOBUF
- This includes connections from registers placed in the ILOGIC or OLOGIC, IDDR, ODDR, ISERDES, and OSERDES to I/O components including IBUF, OBUF, IBUFDS, OBUFDS, IOBUF, and IOBUFDS.
- GT transceiver components
- GTX and GTP transceivers and their dedicated I/O connections.
- Bidirectional ports should be avoided if possible. They do not receive PP_LOCS, so any PP_RANGE or PP_LOCS constraints on bidirectional ports are automatically removed in OOC mode. If bidirectional ports are required, floorplan the associated interface logic to avoid timing issues when the OOC module is imported during the Reuse flow.
Avoid placing any I/O components that connect to each other in different partitions of a design.