Working with Constraints

About Part Constraints

Part Constraints are specified in the “Part Constraint” and represent actual part constraints specified by the manufacturer. A “Part Constraint” needs to specified before adding a Constraint to the diagram.

Adding New Constraints

  1. Select 2 edges. The first edge selected should occur in time before the second.
  2. Add Menu -> Constraint or Ctrl 8 or pop-up menu -> Add Constraint
  3. Enter the Constraint parameters in the Constraint panel and hit the Add button.

Time Calculations

Constraints are used to specified parameters like setup and hold times and pulse width min and max times. When specifying a constraint, the constraint type determines how the slack time calculations are made.

  • Max-Min – measured from source edge max time to the destination edge min time.
  • Max-Max – measured from source edge max time to the destination edge max time.
  • Min-Max – measured from source edge min time to the destination edge max time.
  • Min-Min – measured from source edge min time to the destination edge min time.

Adding Previously Used Constraints

  1. Select 2 edges. The first edge selected should occur in time before the second.
  2. Pop-up menu, select “Add Used Constraint”

Selecting and Deselecting

select

  1. Click on the Constraint name or drag mouse to form rectangle around the Constraint
  2. Hold down the Shft key and click on the Constraint names

deselect

  1. Deselect all. Esc key or click in empty area
  2. Hold down the Shft key and click on the Constraint names

Moving

  1. Select the constraints.
  2. Use Alt and left key to move the Constraints back one half clock cycle
  3. Use Alt and right key to move the Constraints forward one half clock cycle.

Moving the Text Labels

horizontally

  1. Select the Constraint.
  2. Use left or right key to move the label to the left, right, or center position.

vertically

  1. Select the Constraint.
  2. Use up and down keys to move the label. Use the Shft or Alt key with the up and down key to precisely position the text. You can select multiple constraints and move all the labels at the same time.

Deleting

  1. Select the Constraints.
  2. Use the delete key.