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TMS320F28xx hardware design proplem of the Jtag

kang ge
Prodigy 10 points

What the meaning of the sentence "This pin has an internal pulldown and should never be pulled high"? Is that  means /TRST can‘t been high？

  • 0
    TI__Guru 71835 points

    Kang,

    Can you give the literature # for the document where you foudn this note, or just the download URL?  This note is incorrect/incomplete.

    The closest I can find to this is in the datasheet, in the pin description for TRSTn(link below).  I beleive this definition is more clear, but I'd like to make sure that your example gets corrected.  

    What the note should say is that this pin should remain low during during normal operation.  When debugging the device the signal will be driven high by the JTAG emulator.  There are also some boundary scan modes that can be activated when pulling this high in conjuction with the state of EMU0/1.  

    http://www.ti.com/document-viewer/TMS320F28335/datasheet/signal-descriptions-idwrw7-1bcsylv#IDwRW7-1bcsylv

    Best,

    Matthew