What are logical hierarchy and physical hierarchy? How does PlanAhead affect each?
Logical Hierarchy is the hierarchy of the netlist written by synthesis. PlanAhead imports an EDIF netlist and shows the netlist contents.
Using PlanAhead, pblocks (AREA GROUPS) can be created and instances from logical hierarchy can be assigned to these physical blocks. PlanAhead creates a hierarchy different from the logical hierarchy to reflect creation of and logic assignment to these physical blocks.