Article ID: 000079600 Content Type: Troubleshooting Last Reviewed: 11/14/2013

Why does the IO_MAXIMUM_TOGGLE_RATE assignment not work correctly?

Environment

  • Quartus® II Subscription Edition
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    Description

    Due to a problem in the Quartus® II software version 13.0 SP1, you may see that you still get errors regarding differential pins being too close to single-ended pins even though you have set the IO_MAXIMUM_TOGGLE_RATE assignment to 0 MHz.

    Resolution

    To work around this problem, download and install patch 1.02 from the links below. You must install the Quartus II software version 13.0 SP1 before installing this patch.

    When using this patch for designs targeting Cyclone® V devices, apply the maximum I/O toggle rate assignment to affected differential I/O pins. Note that this usage of the maximum I/O toggle rate assignment is different than the usage of this assignment in previous device families. In those device families, the assignment is applied to single-ended I/O pins placed too close to differential I/O pins.

    This is scheduled to be fixed in a future version of the Quartus II software.  Once fixed, you can apply the maximum I/O toggle rate assignment to the single ended I/O pins that are located within the differential pin keep out zones.

    It is not advisable to apply a maximum I/O toggle rate assignment of 0 MHz to any actively switching pin. The pin placement rules in the Quartus II software are enforced to ensure that noisy signals do not corrupt neighboring signals. If you choose to use the toggle rate logic option on switching pins in order to bypass these placement rules, your design may not function as intended.

    Related Products

    This article applies to 1 products

    Intel® Programmable Devices