Pin Properties Dialog Box

You open this dialog box by right-clicking a pin in a Block Design File (.bdf) Definition and then clicking Properties.

Allows you to specify properties for the selected pin.

General tab

  • Pin Name(s)— Allows you to specify the pin name.
  • Default value— Allows you to set the default value of the pin to VCC or GND.

Default values are used when the port is not driven by a node or entity. That is, when an input port is not driven, the underlying input pin will drive all its fan-outs with the default value on the pin.

For example, when a port is not driven, it means that a pin X exists in an entity foo, and the entity foo is instantiated in another design module. However, the port X on the instantiation of foo does not have a signal feeding it in the design. Therefore, the port X is considered unused and the default value of pin X is used to drive the fanouts of pin X.

Default pin values are used only for lower-level pins. Top-level pins that are usually converted to I/O cells do not have these default pin values.

  • Format tab