When running layout, use the Layout Options dialog box to set your layout options.
For ProASIC3/E devices, the I/O Bank Assigner runs automatically after you click OK in the Layout Options dialog box. The I/O Bank Assigner automatically assigns technologies to all I/O banks that have not been assigned a technology.
Select this option to run timing-driven Layout. The primary goal of timing-driven layout is to meet timing constraints, specified by you or generated automatically. Timing-driven Layout typically delivers better performance than Standard layout.
If you do not select Timing-driven layout, Designer runs Standard layout. Standard layout targets efficient usage of the chip resources. Chip performance is not optimized. Timing constraints are not considered by the Layout in standard mode, although a delay report based on delay constraints entered in Timer can still be generated for the design. This is helpful to determine if timing-driven Layout is required.
Select this option to run the placer during Layout. By default, it reflects the current Layout state. If you have not run Layout before, Run Place is selected by default. If your design has already been placed but not routed, this box is cleared by default. You can also select the following incremental placement options.
Incrementally: Select to use previous placement data as the initial placement for the next place run.
Lock Existing Placement (fix): Select to preserve previous placement data during the next incremental placement run.
Incremental options apply to the entire design. For more detailed control of the placer behavior (such as, to fix placement of a portion of the design), use the MultiView Navigator tools or set fixed attributes on the placed instances via PDC (ProASIC3/E) or GCF (ProASICPLUS and ProASIC) constraint files.
Select to run the router during Layout. By default, it reflects the current Layout state. If you have not run Layout before, Run Route is checked. Run Route is also checked if your previous Layout run completed with routing failures. If your design has been routed successfully, this check box is cleared.
Incrementally: Select to fully route a design when some nets failed to route during a previous run. You can also use it when the incoming netlist has undergone an ECO. (Engineering Change Order). Incremental routing should only be used if a low number of nets fail to route (less than 50 open nets or shorted segments). A high number of failures usually indicates a less than optimal placement (if using manual placement through macros, for example) or a design that is highly connected and does not fit in the device. If a high number of nets fail, relax constraints, remove tight placement constraints, deactivate timing-driven mode, or select a bigger device and rerun Layout. Also, see the Advanced Layout options for your device.
There is no “Fix” option for the router. In incremental mode the router tries to preserve the existing routing; there is no guarantee that it will be preserved. Therefore the timing characteristics of the previously routed portion of the design may change, even if the placement was fixed for that portion of the design. For ProASIC3/E families the chance of this is quite small, and the router will print the list of nets that have fixed terminals (i.e. those nets whose every pin's macro has the placement FIX attribute).
Select to run layout multiple times with different seeds. Multiple Pass Layout attempts to improve layout quality by selecting from a greater number of layout results. Click Configure to set your Multiple Pass Configuration.
Click the Advanced button to set Timing-Driven options.
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