How to connect JTAG pins in final PCB design?

are the JTAG input pins, [TDI, TMS, TCK] pull up resistors necessary for normal operation [not debugging] ?

designing a small board and removal of a few resistors would help layout and routing [using a ADuC7061...]

i would add the pull up resistors on to the JTAG cable.or separate board used when debugging.

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    •  Analog Employees 
    on Sep 29, 2010 12:38 PM over 10 years ago

    The pull-up resistors on the JTAG pins, TDI/TCK/TMS are required to ensure that no unexpected glitches occur on any of these lines that corrupt either the flash contents or the ARM7 cores operation.

    There are weak internal pull-ups present internally on each of these pins and these are enabled by default. In a non-noisy environment, these pull-ups may suffice but, for optimum safety, we always recommend the addition of external pull-ups as documented in the datasheet.

    What is most important is that the nTRST/BM pin is pulled high externally by a 13K resistor as mentioned in the datasheet - failure to add this may result in the part entering boot mode after every reset sequence.

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  • 0
    •  Analog Employees 
    on Sep 29, 2010 12:38 PM over 10 years ago

    The pull-up resistors on the JTAG pins, TDI/TCK/TMS are required to ensure that no unexpected glitches occur on any of these lines that corrupt either the flash contents or the ARM7 cores operation.

    There are weak internal pull-ups present internally on each of these pins and these are enabled by default. In a non-noisy environment, these pull-ups may suffice but, for optimum safety, we always recommend the addition of external pull-ups as documented in the datasheet.

    What is most important is that the nTRST/BM pin is pulled high externally by a 13K resistor as mentioned in the datasheet - failure to add this may result in the part entering boot mode after every reset sequence.

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