TPM2CLK Input Not Getting Pulled Up (AC32)

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TPM2CLK Input Not Getting Pulled Up (AC32)

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Luigi
Contributor III

I am using an 'AC32 part and want to use an external clock source for TPM2.  I have an open collector driver currently driving that port pin (PTD4/TPM2CLK/AD1P12) and it is pulled up internally.  When used just as an input port with the internal pull-up enabled, it works fine (i.e. the pullup works).  When used as an external clock input, the pull-up does not seem to be there.

 

The manual states, "When any pin associated with the timer is configured as a timer input, a passive pullup can be enabled."  That sounds like my pull-up should work.  My internal pull-up is still enabled, but it does not pull the pin high when configured as TPM2CLK.  Any clues?

 

Lou

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Luigi
Contributor III
I finally got the answer from my Freescale rep who contacted the factory.  It is as you say.  The timer "inputs" as they say that still have pull-ups enabled are only those used when doing capture.  The documentation is VERY misleading and should be changed.  Thanks for the reply.

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Luigi
Contributor III
I finally got the answer from my Freescale rep who contacted the factory.  It is as you say.  The timer "inputs" as they say that still have pull-ups enabled are only those used when doing capture.  The documentation is VERY misleading and should be changed.  Thanks for the reply.
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J2MEJediMaster
Specialist I

What is the exact name of the Freescale document you were using that was not clear on the subject? I am trying to report this problem so that it can be fixed and prevent this from happening in the future.

 

---Tom

 

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Luigi
Contributor III

Sorry for the delay in getting back to you.  On both the front and back of the document it says, "MC9S08AW60, Rev 2 12/2006".  Thanks for reporting it.

 

Lou

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ThaManJD
Contributor III

I'm pretty sure the manual is referring to the timer channels (for input compare) and not the external timer clock input. If that is a direct quote from a manual then i would agree that the phrase is misleading.

The current ACxx manual appears to be a little bit clearer in this description.

 

JD

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