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TMS320F280040C-Q1: Compensation method for Internal Oscillators

A.W
Intellectual 490 points
Part Number: TMS320F280040C-Q1


Hi

We are facing the issue with the F28004x‘s series's X1/X2 pin damaged.

So we are thinking about using interal oscillator for clock source.

However ,our product uses CAN communication, and the internal oscillator's frequency stability is not good with temperature.

Also it seems that the change of frequency is also no linear ,like 2803x.

Is there a way help us to fix this issue？

Regards

Arrow

  • 0
    TI__Guru* 80640 points

    Unfortunately there is no way to improve the internal oscillator tolerance inside the DS limit of the device.  For the issue with X1/X2 damage, are you able to use the missing clock detect feature of the device to detect this issue and then switch over to the internal oscillator?  If so, is there any settings on the CAN side that we could use in this case to handled the larger tolerance of the clock?  I know that strictly speaking CAN requires 1% accurate clock source, but I wasn't sure if there was some reduced performance option that could tolerate something with more error?

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Intellectual 490 points

    Hi， Matthew

    Is there a relationship of F28004X's internal osicllator 's tolerance with temperature can be  provided?

    As the picture shows, the tolerance can be -3%~3%。I want to fix this problem with slightly changing the CAN baud rate with the temperature to meet at least 1%  tolerance.

    Regards

    Arrow

  • 0 in reply to A.W
    TI__Guru* 80640 points

    Please give me another day to look into this, will reply back tomm.

    Best,

    Matthew

  • +1 in reply to MatthewPate
    TI__Guru* 80640 points

    I believe this is being handled off forum directly with the end customer.  Please let me know if you need me to re-open this thread.  There is no new update on the above information from my side, there is not additional data we can give wrt the exact variation at specific temperatures for the internal oscillator.

    Best,
    Matthew