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AR# 46743

Would Vivado Synthesis be able to infer tristate logic in a lower level module when flatten_hierarchy is set to none?

Description

Would Vivado Synthesis be able to infer tristate logic in a lower level module when flatten_hierarchy is set to none?

解决方案

When the -flatten_hierarchy switch is set to "none," it is not recommended to have tristate at lower level.

In case of a design containing tristate logic, setting flatten_hierarchy to "none" does not actually force the design to preserve hierarchy. 

Vivado synthesis automatically flattens the hierarchy before the I/O insertion stage while trying to infer a tristate primitive for a tristate logic in a lower level module and then rebuild the hierarchy.

The workaround would be either setting -flatten_hierarchy to "full" or "rebuilt" or move the tristate logic to top level in the HDL code.

AR# 46743
创建日期 10/08/2012
Last Updated 04/16/2014
状态 Active
Type 已知问题
Tools
  • Vivado Design Suite