HD.PARTITION and HD.ISOLATED

[jamey.hicks]

I'm trying to understand the scripts in the HD tutorial.

Going through ooc_impl.tcl, it sets either property HD.ISOLATED or HD.PARTITION on [current_design]

It also sets param hd.pplocsFullyInsideRanges.

I could not find documentation on these properties. Could you explain their behavior?

[woodsd · Accepted solution]

These scripts are used for several Xilinx flows.

HD.ISOLATED is for the Xilinx isolation flow. 

HD.PARTITION is for the HD OOC flow, does a few things like preventing optimization in the top-level, and enabling some DRCs. This should be set, and I will file a CR to get this documented in the next realease of UG905.

The param you referenced is just to control the node that is used by the router when routing the interface nets.  The routing of these interface nets only occurs if you have HD.PARTPIN_LOCS in your OOC implementation, and get dropped during assembly (read_checkpoint -cell) anyway. This param is not needed and will not affect your results. It is really more of  a visualization thing. I will file a CR to have this removed from this removed from the scripts to avoid confusion.

[moon5756]

Hi @woodsd,

can you explain the difference between HD.PARTITION and HD.ISOLATED?

According to xapp1222,

Isolated designs must take care to keep the amount of top level logic to a minimum. In a typical
IDF design, the only logic at the top should be Clock logic. Any component that is not part of
an isolated module in the design hierarchy is optimized to the top level. Because isolation is
defined by the HD.ISOLATED attribute being set on a hierarchical module, all top logic is, by
default, NOT isolated. This has the following implications:
• There are no placement constraints on top level logic other than it will not be placed in the fence.

    ° Top level logic can be placed in any isolated region.
• There are no routing restrictions on top level logic other than it will not violate the fence with used PIPs.

    ° Top level routes can route to, from, and through any isolated region.

There's no detailed explanation about HD.PARTITION, but it seems to do the same thing with HD.ISOLATED?