You may receive the following warning message when generating IBIS models for an Arria® II GX device when using the features shown below:
- I/O standard: 3.0V LVTTL
- Series termination: 50 ohm (non-calibrated)
- PCI clamp diode enabled
The IBIS model for this combination of I/O assignments is not available in the Quartus® II software versions 12.0sp2 and earlier. The IBIS model for this combination of I/O is available in the general IBIS model for Arria II GX devices which may be downloaded from Altera IBIS Models.
Remove the PCI clamp diode assignment from these I/O types to allow generation of the IBIS model from the Quartus II software. You may then reinstate the PCI clamp diode in your Quartus II project and use the model for this I/O from the general Arria II GX device IBIS model.
This problem is scheduled to be fixed in a future version of the Quartus II software.