[ANSWERED/SOLVED] Jlink pin status.

  • [ANSWERED/SOLVED] Jlink pin status.

    Hello.

    I am new owner of JLink and i am glad to have it. It,s powerful tool in first minute I see the difference form other probes.

    In SWD interface what status have pins from JTAG interfejs?

    The post was edited 1 time, last by tadzik85 ().

  • Hi,

    In SWD interfejs what status have pins from JTAG interfejs?

    I guess you mean "interface", correct?
    All unused pins are usually configured for input mode on the J-Link side, so J-Link is not driving them.


    - Alex
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  • Hi,

    Yes, as long as you make sure that you *never* start J-Link with the incorrect interface being selected.
    Otherwise, some series resistors to limit the current may be an option.

    Or: Do not connect them to J-Link at all.


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
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  • Hi,

    Then you should be careful regarding the interface selection...
    But on most development boards there are series resistors on these lines.


    - Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • In JLink manual :
    "Version 6.0 (Obsolete)
    Identical to version 5.4 with the following exception:
    ï Outputs can be tristated (Effectively disabling the JTAG interface)
    ï Supports SWD interface.
    ï SWD speed: Software implementation. 4 MHz maximum SWD speed.
    ï J-Link supports SWV (Speed limited to 500 kHz)"

    How to interprete this?
    They are Hi-Z when use SWD or without any connection with target?

  • Hi,

    It is to be interpreted as it is stated...
    J-Link *can* tri-state the target interface. It does not say under which circumstances which pins are tri-stated etc.
    Please just refer to my previous posts.


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • Hi,

    J-Link does not set any breakpoints on its own.
    It is always the top-level software that controls the DLL which does this.
    In this case, I assume that you are using IAR EWARM for debugging, correct?

    If yes, in your case, the project seems to be configured for using printf() via semihosting, which requires a breakpoint at address 0x8.


    If you do not want this to happen, just change this setting to "None".


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • Hi,

    Yes, the breakpoint at 0x8 is mandatory for semihosting calls,
    and will be set when semihosting is enabled in GDB Server (monitor semihosting enable).
    If you do not enable semihosting the breakpoint will not be set automatically.

    Best regards
    Johannes
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
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