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Serial wire debug pin is pulled down/up internally.

Question asked by jun yamada on Dec 3, 2018
Latest reply on Dec 4, 2018 by Robin_Shen

Please kindly advise.


I have a question about SWD hardware.

In the manual "Document Number: MKMxxZxxACxx5RM Rev. 1, 09/2014"
"9.2 Debug Port Pin Descriptions" has the following description.

Serial Wire Clock. This pin is the clock for debug logic when in Serial Wire Debug mode. This pin is pulled down internally.
Serial wire debug data input / output. The SWD_IO pin is used by an external debug tool for communication and device control.

There are SWD_CLK pull-down and SWD_IO pull-up.
I have a question about this.
① What is the value of this pull-up resistor and pull-down resistor?
② Does it not have to pull up pulled down externally?
    Or should I do it?
③ If the pull-up / pull-down is required, how much resistance?


I do not have good English.


Thank you.