Article ID: 000078521 Content Type: Product Information & Documentation Last Reviewed: 07/30/2015

How do I constrain PLL clocks when using clock switchover in 28-nm devices?

Environment

  • Quartus® II Subscription Edition
  • PLL
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    Description

    Due to a problem in the Quartus® II software version 10.1 and later, the derive_pll_clocks command does not correctly constrain all clocks when using Altera_PLL with PLL clock switchover. This problem affects designs targeting Stratix® V, Arria® V or Cyclone® V devices. Instead of creating clocks associated with each input reference clock, derive_pll_clocks only creates clocks for the first reference clock.

    Resolution

    To correctly constrain Altera_PLL outputs for each reference clock, use create_generated_clock commands as described in the document below. The document includes instructions for how to create these commands as well as example commands based on the example design below.

    This problem is scheduled to be fixed in a future release of the Quartus II software.

    Related Products

    This article applies to 15 products

    Arria® V SX SoC FPGA
    Cyclone® V ST SoC FPGA
    Arria® V ST SoC FPGA
    Arria® V GX FPGA
    Arria® V GT FPGA
    Cyclone® V E FPGA
    Cyclone® V SE SoC FPGA
    Stratix® V E FPGA
    Cyclone® V SX SoC FPGA
    Cyclone® V GT FPGA
    Stratix® V GX FPGA
    Stratix® V GT FPGA
    Cyclone® V GX FPGA
    Stratix® V GS FPGA
    Arria® V GZ FPGA