Make Pblocks as Rectangular as Possible to Avoid Unroutability at the Edges - 2021.1 English

Versal ACAP Hardware, IP, and Platform Development Methodology Guide (UG1387)

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2021.1 English

For Pblocks with CONTAIN_ROUTING enabled, the router has less solution space at the corners of the Pblock. To avoid unroutable situations, Xilinx recommends making Pblocks as rectangular as possible. Using another shape results in more corners for the Pblock, which can introduce congestion at those corners.

In the following example, report_design_analysis reports a congestion of level 6 at the edges of a non-rectangular static Pblock. This approach is not recommended.

Figure 1. Non-Rectangular Static Pblock with Congestion at the Corners

The following example shows the same design but with a rectangular Pblock. With this approach, report_design_analysis reports a reduced congestion level 5 with no congestion reported at the edge of the Pblock. This is the recommended approach.

Figure 2. Rectangular Static Pblock with Reduced Congestion