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McAsp0 and OPP50

Martin H.
Expert 2315 points
Hello,

in the PinMuxRelease_Notes.txt I found this remark:

    "9. Pin Multiplexing: Valid IO Sets and Restrictions (AM335x device only)

    ...
    MCASP0 Interface
    Operation of MCASP0 is not supported for OPP50."


As far as I understand OPP50 has something to do with reduced power consumption by
reducing clock frequencies.
So when an application is derived from one of those StarterWare examples, in which mode is it? OPP100?
Must I fear to accidentally enter the OPP50 mode so that McAsp0 doesn't work anylonger?

It would be nice if somebody could bring some light into the darkness. ;-)

Thank you!

Martin

  • 0
    Guru 92251 points

    Martin H. said:
    So when an application is derived from one of those StarterWare examples, in which mode is it?

    In AM335X_StarterWare_02_00_01_01\bootloader\src\armv7a\am335x\bl_platform.c there is a function BootMaxOppGet which determines the maximum frequency supported by the AM335x device, which is used while during setup of the Pll, DDR and Uart. Therefore, I think the bootload will set the highest supported frequency which will be in use unless the StarterWare makes calls to change the OPP level.

    [This isn't a complete answer, but hopefully provides something to investigate further]

  • 0 in reply to Chester Gillon
    TI__Intellectual 1480 points

    Martin,

    When StarterWare application is loaded it is not in OPP50.

    The reduction in frequency may pose limitations on the operating of the McASP module.

    It is recommended not to operate McASP in OPP50.

    Regards,

    Ramesh D

  • 0 in reply to Ramesh Dandamudi
    Expert 2315 points

    Good to know. Thank you.

    Regards,

    Martin