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F28M35H52C: Missing clock detection

LukasWuethrich
Prodigy 50 points
Part Number: F28M35H52C
Other Parts Discussed in Thread: TMDSCNCDH52C1, CONTROLSUITE

hello everybody

I try to understand and implement the feature "missing clock  detection logic". I watched already the training (https://training.ti.com/concerto-f28m3x-microcontroller-training-part-2-system?cu=72092) and read the technical reference manual of the concerto F28M35x (chapter 1.6.2 and 1.6.3).

But I can't find any information about the tolerance of the internal oscillator (10MHz). How it is defined? The information would be helpful for an estimation on my part

Is there a code example for the "missing clock detection logic" and the "PLLSLIP Detection" available? I have the eval board TMDSCNCDH52C1 and I use the Code Composer Studio 8.1.0.

Thanks for your help
Lukas

  • 0
    TI__Guru 71815 points
    Lukas,
    While there is not a guaranteed specification I beleive it would be safe to assume 10MHz +/-1MHz for this detection clock. This should give tolerance over the full operational range of the device.

    In terms of example code the sysctrl.c file located in C:\ti\controlSUITE\device_support\f28m35x\v220\MWare\driverlib\ includes both the missing clock detect and PLL slip in the SysCtlClockPLLConfig() function call at line 1202.

    Best,
    Matthew
  • 0 in reply to MatthewPate
    Prodigy 50 points
    Hi Matthew

    Thank you for your reply.

    How can I set the lower and higher limit for the PLL slip detection? Is there an API function or do I have to write directly into the register MCLKLIMIT?
    In the technical manual is a note (www.ti.com/.../spruh22h.pdf, Page 223), that I have to set MCKLDETEN = 0 when I set this limits. But I can't find a definition for the register MCKLDETEN. Is it a type? Is MCKLDETEN MCKLEN meant?

    Thanks,
    Lukas
  • 0 in reply to LukasWuethrich
    TI__Guru 71815 points
    Lukas,
    The best I can tell there is not a limit on the slip detection that can be set by the user, and I beleive the missing clock detect EN bit is MCLKNMIEN. Page 123 does a better job explaining the order of operation wrt the limits and enables.

    Matt
  • 0 in reply to MatthewPate
    Prodigy 50 points

    Matt, thank you for your answers and your help!