Article ID: 000084379 Content Type: Troubleshooting Last Reviewed: 04/22/2013

Do RUP and RDN pins support calibrated series on chip termination (OCT) when used as regular I/O in Arria II GX devices?


  • Quartus® II Subscription Edition

    No, RUP and RDN pins when used as regular I/O do not support calibrated series OCT in Arria® II GX devices.  RUP and RDN pins cannot receive calibrated codes from termination blocks located in other I/O banks, this is a hardware limitation.

    The Quartus® II software will allow a design to compile if an RUP or RDN pin is used as a regular I/O pin configured with calibrated series OCT.  The fitter report will show the I/O pin is using calibrated series OCT.  This is a bug in the Quartus II software.

    If you are using RUP or RDN pins as regular I/O and set the output buffer to use calibrated series OCT, the output will not toggle.  This is because no transistors in the output buffer will be enabled during OCT calibration. 

    Resolution You can use non-calibrated series OCT, or any supported drive strength setting for RUP and RDN pins being used as regular I/O pins.

    Related Products

    This article applies to 1 products

    Arria® II GX FPGA



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