Hierarchical ports and hierarchical pins provide connection between levels of hierarchy on a schematic page.
Inside a hierarchical block, a hierarchical pin provides only vertical (downward-pointing) connection. It is connected by name to hierarchical ports on schematic pages within the attached schematic folder or to the appropriate signals in the VHDL entity port definitions. You can think of its function as bringing a net "up" from the attached implementation into the hierarchical block (but not out onto the schematic page).
Outside a hierarchical block, a hierarchical port provides vertical (upward pointing) and lateral connections. Its connected vertically to the like-named hierarchical pin inside any hierarchical block to which it is attached. Its connected laterally to like-named nets, hierarchical ports, and off-page connectors within the same schematic folder. You can think of its function as carrying a net out of the schematic folder.
Before you create or re-size a hierarchical block, make sure the Snap to grid option is turned on (from the schematic page editor's Options menu, choose ). If the hierarchical block is on Fine grid, then hierarchical pins inside it are also on Fine grid—even if you change the Snap to grid setting before you place them—and it may be difficult to connect to these off-grid hierarchical pins.
A part with an attached schematic folder functions exactly like that for hierarchical blocks, and pins on such a part function exactly as described for hierarchical pins within a hierarchical block. You can use the same attached schematic folder for either method of defining a hierarchy. The only difference between the two methods is that a part with an attached schematic folder is easier to reuse. See Creating parts and assigning properties for related information.
If you choose the on a non-primitive part or hierarchical block, and Capture cannot find the attached implementation, Capture creates a schematic folder or VHDL model in the active design.
If you attach an existing implementation to a hierarchical block, Capture automatically creates the hierarchical pins that correspond with the schematic folder's hierarchical ports or the VHDL models port definitions. If you descend the hierarchy on a hierarchical block whose implementation does not yet exist, then Capture automatically creates the hierarchical ports (for schematics) or port definitions (for VHDL models) that correspond with to the hierarchical pins of the hierarchical block.
If you attach external schematic folders or other files to hierarchical blocks in a design or parts in a library, be sure to include the attachments when you pass the design or library to a board fabrication house or to another engineer. Attached schematic folders and other files are not carried along automatically when you copy or move a part, schematic folder, or schematic page to another library, design, or schematic folder. Only the "pointers" to the attached schematic folders and files—that is, their names and the names of the designs or libraries that contain them—are carried along.
Attached files work much like their counterparts in email—they do not provide an alternative definition of the part (as do attached schematic folders).
When you attach a schematic folder to a part or hierarchical block, you can specify a full path and file name in the Library field. So, although you can specify a library that has not been saved, you should not try to descend into the attached schematic folder until the library that contains the schematic folder has been saved.
If you do not specify a full path and file name in the Library field, Capture expects to find the attached schematic folder in the same design as the part of hierarchical block to which it is attached. If the specified schematic folder does not exist in either the design or library, Capture creates the schematic folder when you descend the hierarchy on the part or hierarchical block.
For compatibility with future versions of Windows, Capture preserves the case of the path and filename as you specify them in the Library field.
Note: The is restricted to the active schematic page—it does not follow hierarchical blocks, hierarchical ports, or off-page connectors across schematic folders or schematic pages. For more information, see Tracing a net.
Remember that nets on a schematic page are electrically connected by name, by alias, or by connection to a named hierarchical port or off-page connector.
To connect pages vertically (through a hierarchical block)
If necessary, place the hierarchical block and attach the implementation (see Creating hierarchical blocks for instructions). Complete these steps to bring the net into the hierarchical block:
- Bring the net into the hierarchical block:
- Select the hierarchical block.
- From the Place menu, choose Hierarchical Pin.
- Enter a name and choose OK.
- Place the symbol within the boundaries of the selected hierarchical block.
This hierarchical pin is downward pointing—it is connected to any like-named hierarchical port on any schematic page in the attached schematic folder.
To complete the procedure, carry the net up to the hierarchical block. - Open a schematic page contained in the schematic folder attached to the hierarchical block mentioned above.
- Make sure no hierarchical block is selected.
- From the Place menu, choose Hierarchical Port.
- Select a symbol, enter the name used in step 3 of the preceding sequence, and choose OK.
- Place the symbol anywhere (except inside a hierarchical block) on the schematic page.
This hierarchical port is upward pointing—it is connected to any like-named hierarchical pin inside any hierarchical block to which it is attached. - If necessary, use off-page connectors to carry the net to other schematic pages in the same schematic folder (see Placing off-page connectors for instructions).
- Be careful not to create recursion in your design. Capture cannot prevent recursion, and the does not report it.
- Recursion causes Capture to process infinitely as it tries to expand the design, resulting in the loss of any changes you've made to your design since it was last saved.
- You can use the copy and paste keyboard shortcuts (CTRL+C and CTRL+V) to enter the same name in the Name text field of both dialog boxes.
To connect hierarchical ports or off-page connectors with nets
- Extend the net to the hierarchical port or off-page connector by placing a wire or bus.
OR
- Select the hierarchical port or off-page connector and choose Properties from the Edit menu.
- In the Name or Value field, type the name of the net, and click OK.
OR - Select the hierarchical port or off-page connector's name and choose Properties from the Edit menu.
- In the Name or Value field, type the name of the net, and click OK.