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Altera_Forum
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9 years ago

Cyclone 5 PLLs

Is there a programatic way to re-configure the on chip PLLs? I don't mean loading a new .mif file, but rather having the embedded OS calculate the constants required to re-load the PLL for a different frequency?

I would like to have the embedded OS be able to generate a wider range of frequencies off of the base clock.

Thanks,

Jon Herr

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    --- Quote Start ---

    Is there a programatic way to re-configure the on chip PLLs? I don't mean loading a new .mif file, but rather having the embedded OS calculate the constants required to re-load the PLL for a different frequency?

    I would like to have the embedded OS be able to generate a wider range of frequencies off of the base clock.

    Thanks,

    Jon Herr

    --- Quote End ---

    Hi Jon,

    If you are referring to the HPS PLL, you can refer to the chapter "Clock Manager" in the Technical reference manual here:

    https://www.altera.com/en_us/pdfs/literature/hb/cyclone-v/cv_5v4.pdf

    Check the "Hardware-Managed and Software-Managed Clocks" section for details on the clock management.