ALT_BIDIR_BUF Primitive
The ALT_BIDIR_BUF primitive allows you to make low-level assignments with the altddio_bidir Altera® IP. This primitive allows you to do the following:
- Make a location assignment
 - Make an I/O standards Definition assignment
 - Make a drive strength (current strength) assignment
 - Make a slew rate assignment to the bidirectional pin connected to the altddio_bidir Altera® IP
 - Make an on-chip termination assignment
 - Enable bus hold circuitry
 - Enable weak pull up resistor
 
This primitive is available for CycloneIII and StratixIII devices only.
The ALT_BIDIR_BUF primitive is not supported by AHDL.
Note: 
- This primitive can be used only with an altddio_bidir Altera® IP.
 - Trying to set other parameters not listed in the Parameters table on the ALT_BIDIR_BUF primitive results in errors.
 - For information about Quartus® Prime primitive instantiation, see Using a Quartus® Prime Logic Function.