[SOLVED] How to j-tag chain two Nucleo G431 MCU's

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  • [SOLVED] How to j-tag chain two Nucleo G431 MCU's

    Hi All,

    This is updated 9/17/20 with my latest progress.

    My interconnection of the two boards was wrong due to a misunderstanding of how TDO is routed on the board. I was able to get the Gerber files and review them so this update includes that information.

    I interconnected the boards per the new diagram. The connection of the first device TDO to the JTag TDI required removing SB15 and soldering in two wires to go to the appropriate connection. The photo shows the modification to SB15 with wires and the 2nd photo shows the two boards connected.

    I can now run J-LINK through the Keil debugger and it see's all 4 devices (see attached). Devices 0 and 2 are the CoreSight JTAG DP and devices 1 and 3 are "Unknown JTAG Devices". I can go into the debugger setup and see the 4 devices and change the selected device to debug.

    My issue now is I can single step through code on device #0 but I can't seem to get control of device #2, even though I change it in the debugger setup.
    Working with JLink.exe command line tools I was able to access device #1 as [Pre Dpre] (0,0) and halt and run the device. Also with (9,2) I was able to connect to device #3 and halt and run it.

    My only open issue now is while running JLink debugger from Keil 5.3.0 I can see all 4 devices but can only access device #0
    Images
    • two_MCU_jtag_diagram.GIF

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    • Jtag_Debug_screen.png

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    • IMG_2107.JPG

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    • IMG_2108.JPG

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    The post was edited 4 times, last by btremaine: adding block diagram added request for help :) update with progress 9/17/20 ().

  • Hi,
    Thank you for your inquiry.
    We are sorry for the delay in response. The last weeks have been very busy.

    From what you say, this issue might be connected to KEIL.
    Does debugging via SEGGER Ozone work as expected?
    segger.com/downloads/jlink#Ozone

    Best regards,
    Fabian
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    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 Brian,
    Good to hear that you are up and running again.

    We will close this thread now.

    Best regards,
    Fabian
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    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.