Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Max v cpld dpll

Hi All,

I am new to the Altera CPLDs. Come from the X-Company side of things. The Max V CPLD looks really cool. What with user Flash memory, Internal programmable Oscillator, low power states. Is there a DPLL available on these devices. I found references to that on the product landing page but the data sheet does not talk about that. Can someone please clarify?

thanks

ANanth

13 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    The DPLL feature on MAX V devices is interesting. However, the overview page has this note:

    --- Quote Start ---

    Note:

    1. Digital PLL is an optional intellectual property (IP) that can be instantiated into unused LEs.

    --- Quote End ---

    So is it just an IP feature? No specific silicon support? If that is the case, then why it is specific and restricted to MAX V?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    MAX V effectively is MAX II, with identical specification and core structure, and minimal changes, extending Z (zero power) to higher densities and introducing new packages. Rated number of programming cycles has been gracefully increased from 100 to 1000 for the UFM.

    MAX II/V has an internal RC oscillator, required for operation of the internal flash and also exposed to user logic. It's not programmable. No new clock processing features are provided according to the datasheet.

    The DPLL point is interesting indeed. It still written on the MAX V product page.

    http://www.altera.com/products/devices/cpld/max-v/mxv-index.jsp

    --- Quote Start ---

    ...features including:

    Digital PLLs (DPLLs), which enable flexible implementation of designs requiring frequency multiplication or phase shifting

    --- Quote End ---

    It's also written in the MAX V solution sheet http://www.altera.com/literature/po/ss-maxv-cplds.pdf

    --- Quote Start ---

    MAX V Silicon Features and Benefits

    ...

    Phase-locked loops (PLLs) - Digital PLL implementation provides flexible implementation for designs needing frequency multiplication or phase shifting.

    --- Quote End ---

    So either the "clock network" chapter has been forgotten in the MAX V datasheet, or the feature has been previously planned but wasn't implemented, or it has been implemented, but doesn't work.
    • Grantwt's avatar
      Grantwt
      Icon for New Contributor rankNew Contributor

      Is there anywhere I find information on the number of PLL available the operating frequency range and the loop filter time constant. There seem to be a lot information about the MAX V chips, next nothing on the DPLL's and the possible configurations. Are there any pdf files I can look at with this information in?