The ALT_BIDIR_DIFF primitive allows you to name and connect positive and negative pins when the altddio_bidir megafunction is used. This primitive allows you to do the following:

  • Make a location assignment
  • Make an I/O standards Definition assignment
  • Enable bus-hold circuitry
  • Enable a weak pull-up resistor
  • Make slow slew rate assignments
  • Make an on-chip termination (OCT) assignment to an input pin from a lower-level entity

This primitive is available for CycloneIII devices only.

The ALT_BIDIR_DIFF primitive is not supported in the Altera Hardware Description Language (AHDL) Definition.

  • This primitive can be used only with an altddio_bidir megafunction.
  • Trying to set other parameters not listed in the Parameters table on the ALT_BIDIR_DIFF primitive results in errors.
  • For information about Quartus® Prime primitive instantiation, go to Using a Quartus® Prime Logic Function.