Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

DCM (Digital Clock Manager)

  1. Jun 21, 2007 #1
    I am tasked to use the DCM in Xilinx's architecture wizard. Can anyone explain what is the function of a DCM and how does it actually work? What are the inputs and outputs of a typical DCM? many thanks!
  2. jcsd
  3. Jun 21, 2007 #2


    User Avatar

    Check the User Guide documentation for the part you're
    using. e.g. for the Spartan 3 / Spartan 3A DCMs:
    http://direct.xilinx.com/bvdocs/userguides/ug331.pdf [Broken]
    q.v. pages 61...

    Using Digital Clock Managers (DCMs)
    Digital Clock Managers (DCMs) provide advanced clocking capabilities to Spartan-3
    Generation FPGA applications (Spartan-3, Spartan-3E, Spartan-3A, Spartan-3AN, and
    Spartan-3A DSP families). Primarily, DCMs eliminate clock skew, thereby improving
    system performance. Similarly, a DCM optionally phase shifts the clock output to delay the
    incoming clock by a fraction of the clock period. DCMs optionally multiply or divide the
    incoming clock frequency to synthesize a new clock frequency. The DCMs integrate
    directly with the FPGA’s global low-skew clock distribution network.
    DCMs integrate advanced clocking capabilities directly into the FPGA’s global clock
    distribution network. Consequently, DCMs solve a variety of common clocking issues,
    especially in high-performance, high-frequency applications:
    • Eliminate Clock Skew, either within the device or to external components, to
    improve overall system performance and to eliminate clock distribution delays.
    • Phase Shift a clock signal, either by a fixed fraction of a clock period or by
    incremental amounts.
    • Multiply or Divide an Incoming Clock Frequency or synthesize a completely new
    frequency by a mixture of clock multiplication and division.
    • Condition a Clock, ensuring a clean output clock with a 50% duty cycle.
    • Mirror, Forward, or Rebuffer a Clock Signal, often to deskew and convert the
    incoming clock signal to a different I/O standard—for example, forwarding and
    converting an incoming LVTTL clock to LVDS.
    • Any or all the above functions, simultaneously.
    Last edited by a moderator: May 2, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook