When I place two flip-flops with opposite clock polarities into the same slice in Floorplanner, then run my design through MAP, the following errors are reported on these constraints:
"ERROR:Pack:679 - Unable to obey design constraints (LOC = ...) which require the combination of the following symbols into a single slice component:
FLOP symbol ...
FLOP symbol ...
The clock signals don't agree. Please correct the design constraints accordingly."
Why does this occur?
Flip-flops with different clock polarities must be placed in separate slices. To avoid this MAP error, place flip-flops that have different clock polarity into different slices.
The Floorplanner will include more complete DRC checks in a future software release.
| AR# 6968 | |
|---|---|
| Date | 12/15/2012 |
| Status | Active |
| Type | General Article |