Introduction to Quartus® II

CHAPTER 9: TIMING CLOSURE
USING THE TIMING CLOSURE FLOORPLAN
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Routing delays: display routing delays to or from specific logic cells,
I/O cells, embedded cells, or pins; between selected nodes; or along one
or more critical paths.
Connection counts: show or hide the number of connections to a
selected object, from a selected object, or between selected objects.
Physical timing estimates: displays the approximate delay from one
physical resource to another physical resource. Once you select a
physical resource, the delay is represented graphically by the shade of
potential destination resources (the darker the resource, the longer the
delay) and the delay to a destination resource is shown numerically by
placing the mouse over another physical resource.
Routing congestion: displays a graphical representation of the routing
congestion in a design. The darker the shading, the greater the routing
resource utilization. You can select a routing resource and then specify
the congestion threshold (displayed as red areas in the device) for the
resource.
Critical paths: displays the critical paths in a design, including path
edges and routing delays. The default critical path view shows the
register-to-register paths. You can also view all the combinational
nodes for the worst-case path between the source and destination
nodes. You can specify criteria for filtering which critical paths are
displayed by specifying the clock domain, source and destination node
names, the number of critical paths to display, and slack.
You can also view the routing information for LogicLock regions in the
design, including connectivity and intra-region delay. LogicLock region
connectivity displays the connectivity between entities assigned to
LogicLock regions in the design and intra-region delay displays the
maximum time delay between source and destination paths in a LogicLock
region, including its child regions.
The Equations window displays routing and equation information for pin,
I/O cell, logic cell, and embedded cell assignments. When you turn on
Equations from the View menu, the Equations window is displayed at the
bottom of the Timing Closure floorplan window as shown in Figure 2.
170 ■ INTRODUCTION TO QUARTUS II ALTERA CORPORATION