New Constraint Dialog Boxes
This section describes the dialog boxes that are used to create new constraints.
For a description of the directional buttons (>, <, >>, and <<) see “Moving Items in List Boxes.”
Clock Period Dialog Box
The Clock Period dialog box enables you to create a global clock period constraint.
Field
| Description
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|---|
Time Spec
| A text box in which you type the name of the timing specification for the period. The name should be entered in the form TSid, where id is a unique name. The name can consist of letters, numbers, or the underscore character (_). If you do not enter TS, the software will automatically prepend it to your id.
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Clock Net Name
| By default, this field will be filled in with the name of the clock net associated with the row you selected
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Explicit
| A button that when selected indicates that the specified clock period is to be independent of any other clock period specification.
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Time
| A text box for entering a value which represents the duration of the clock period.
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Units
| A pull-down list from which you select a time unit for the clock period.
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Start High/Start Low
| Buttons that when selected specify that the initial pulse for the clock period is to be in a high or low state.
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Time High/Low
| A text box in which you enter the duration of the high (or low) pulse for the clock period. The default is %, which is the percentage of the period that the pulse is high or low.
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Units
| A pull-down list from which you select a time unit for the duration of the high or low clock pulse.
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Relative to other Period Time Spec
| A button that when selected specifies that the clock period is to be relative to another clock period specification.
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Reference Time Spec
| A pull-down list from which you select the name of the time specification relative to the clock period.
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Multiply by/Divide by Factor
| Buttons and a text box that specify the factor of multiplication or division of the relative clock period.
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Location Dialog Box
This dialog box allows you to lock a user-defined port to a device pin.
Field
| Description
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|---|
Location
| A text box in which you enter the device pin identification.
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Time Group Dialog Box
This dialog box enables you to create a new Groups by Elements (TIMEGRP) name and its members.
The functions of the dialog box are described below.
Field
| Description
|
|---|
Time Group_Name
| A text box in which you enter a name for the new time group.
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Design Element Type
| Pull-down list. Select one from among FFS, PADS, RAMS or LATCHES.
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Name Available
| Name is FFS, PADS, RAMS or LATCHES. Lists all of the names of the available design element type selected from the Design Element Type pull-down list.
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Time Group Members
| A list identifying elements selected from the Name Available window. The names on this list constitute the new time group.
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Time Name Dialog Box
This dialog box enables you to create a new Groups by Net (TNM). A TNM is an attribute that can be used to identify the elements that make up a group, which can then be used in a timing specification.
Field
| Description
|
|---|
Time Name
| A text box in which you enter the new timing name. The name can consist of any combination of letters, numbers, or underscores. Keep the TNM short for convenience and clarity.
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Design Element Type
| A pull-down list. Possible selections are Clocks, Clock Enables, All nets, FFS, PADS, RAMS, LATCHES.
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Instances (or Clock Nets) Available
| A Scrollable list giving all of the design's available instances or clock nets, depending upon your selection from the Design Elements Type field. Selected names from this list become members of a group which is identified by the time name.
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Time Name Targets
| A scrollable list that includes all of the members of a group which is identified by the time name. These are names that you selected from the Instances (or Clock Nets) Available field.
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Timing THRU Points (TPTHRU) Dialog Box
The Timing THRU Points (TPTHRU) dialog box allows you to specify an intermediate point in a path and the maximum allowable delay from a source through the intermediate point to a destination.
Field
| Description
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|---|
TPTHRU Name
| A unique name identifying the constraint.
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Design Element Source
| A TPTHRU constraint can be placed on a net or an instance.
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Available Nets/Instances
| Lists the available nets or instances, depending upon your selection from the Design Element Source pull-down list.
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TPThru Targets
| Lists the timing point(s) in the path that you have specified. If you selected more than one timing point, they will be treated as a group.
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Pad to Setup Dialog Box
The Pad to Setup dialog box allows you to enter a Pad to Setup constraint.
NOTEThe appearance of the Pad to Setup dialog box varies slightly depending upon which tab window you use to open the box.
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Field
| Description
|
|---|
Pad Net
| This field applies only if you opened the Pad to Setup dialog box from the Ports tab window. Select this if your constraint applies only to a specific pad net, then select the name of the pad net from the pull-down list.
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Pad Group
| This field applies only if you opened the Pad to Setup dialog box from the Advanced tab window. Select this if your constraint applies to a group of pads, then select the name of the group from the pull-down list.
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Time Requirement
| The amount of time that data must arrive at the edge of a device before the next clock arrives at the edge of the device.
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Relative to Clock Net
| The clock net driving the synchronous elements
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Register Timegroup
| This field applies only if you opened the Pad to Setup dialog box from the Advanced tab window. A user-defined register timegroup
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Clock to Pad Dialog Box
The Clock to Pad dialog box allows you to enter a Clock to Pad constraint.
NOTEThe appearance of the Clock to Pad dialog box varies slightly depending upon which tab window you use to open the box.
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Field
| Description
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|---|
Pad Net
| This field applies only if you opened the Clock to Pad dialog box from the Ports tab window. Select this if your constraint applies only to a specific pad net, then select the name of the pad net from the pull-down list.
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Pad Group
| This field applies only if you opened the Clock to Pad dialog box from the Advanced tab window. Select this if your constraint applies to a group of pads, then select the pad group name from the pull-down list.
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Time Requirement
| The amount of time that data must leave the edge of the device after the current clock edge arrives at the edge of the device.
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Relative to Clock Net
| The clock net driving the synchronous elements
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Register TimeGroup
| This field applies only if you opened the Clock to Pad dialog box from the Advanced tab window. A user-defined register timegroup.
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From/THRU/TO Dialog Box
The From/Thru/To dialog box allows you to stipulate a maximum allowable time delay between groups of elements and through specified intermediate points and to specify paths that will be ignored by timing.
Field
| Description
|
|---|
Time Spec
| The name of the time specification in the form TSid, where id is a unique name. The name can consist of letters, numbers, or the underscore character (_). If you do not enter TS, the software will automatically prepend it to your id.
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From Group
| The source group to be acted upon by the constraint.
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To Group
| The destination group to be acted on by the constraint.
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THRU Points (Optional)
| Intermediate points that have been defined with the Constraints Editor Timing THRU Point dialog box
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Explicit
| Defines the time specification to be non-relative to any other time specification. This is the default configuration for the Slow/Fast Path Exceptions constraint.
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Time
| The maximum delay between the source group and the destination group.
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Units
| A unit of time to be applied to the entry in the Time field.
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Relative to other path specification
| Identifies the new time specification as one that is relative to another time specification. This is the default configuration for the Multicycle Paths constraint.
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Multiply by/Divide by
| Selects the mathematical operation between the new time spec and the relative time spec.
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Factor
| A value for the multiplication or division.
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Mark as false paths
| Specifies that the selected groups and timing points will be ignored by timing. This is the default configuration for the False Paths constraint.
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Timing Ignore Dialog Box
The Timing Ignore dialog box allows you select timing specifications containing a specified net which will be ignored by timing.
Field
| Description
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|---|
Net
| The name of the net that you wish to be ignored by timing.
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TIMESPECs Available
| The available time specifications containing the selected net. If you do not select any timespecs, the constraint will apply to all of the timespecs displayed in this list.
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Ignored TIMESPECs
| Time specs selected from the TIMESPECs Available list.
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