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

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