External Memory Interface Handbook Volume 3: Reference Material

ID 683841
Date 7/24/2019
Public
Document Table of Contents

1.9.1. The DLL and PLL Sharing Interface

You can generate the UniPHY memory interface and configure it to share its PLL, DLL, or both interfaces.

By default, a UniPHY memory interface variant contains a PLL and DLL; the PLL produces a variety of required clock signals derived from the reference clock, and the DLL produces a delay codeword. In this case the PLL sharing mode is "No sharing". A UniPHY variant can be configured as a PLL Master and/or DLL Master, in which case the corresponding interfaces are exported to the UniPHY top-level and can be connected to an identically configured UniPHY variant PLL Slave and/or DLL Slave. The UniPHY slave variant is instantiated without a PLL and/or DLL, which saves device resources.

Note: For Arria II GX, Arria II GZ, Stratix III, and Stratix IV devices, the PLL and DLL must both be shared at the same time—their sharing modes must match. This restriction does not apply to Arria V, Arria V GZ, Cyclone V, or Stratix V devices.
Note: For devices with hard memory interface components onboard, you cannot share PLL or DLL resources between soft and hard interfaces.

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