• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 29 subscribers
  • Views 203 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LAUNCHXL2-RM46: External JTAG Debug (TEST PIN)

ArTzy
Genius 13959 points
Part Number: LAUNCHXL2-RM46
Other Parts Discussed in Thread: TM4C129ENCPDT, RM46L852, MSP430F5529, MSP-EXP430F5529LP

Hi Experts,

We have this query coming from client, asking about the TEST pin in the LAUNCHXL2-RM46 development kit.

The table on page 11 of the user guide called "HerculesTm TMS570LS12x/RM46 LaunchPad User's Guide" appears the debug pin dedicated to use a external JTAG. I have got a XDS110 JTAG Debug Probe, this JTAG debug probe has got the SWDIO/TMS, nTRST/TRSTn, TDI, GND, TDO/SWO, VTRef (3.3), RTCK and TCK (All of these pins are defined by the RM46L852CPGET microcontroller), but not appears specified the TEST pin defined by the microcontroller, instead the KEY pin appears. Therefore, I suppose that the KEY pin, that is called in the table on page 11 as EXTERNAL_DEBUG, is actually the TEST pin. Is this correct?

For your assistance.

Regards,
Archie A.

  • 0
    TI__Mastermind 39295 points

    Hi Archie,

    We started to work on your issue and will provide an update soon.

    --

    Thanks & regards,

    Jagadish.

  • 0 in reply to jagadish gundavarapu
    TI__Mastermind 39295 points

    Hi Archie,

    I will explain the how "EXTERNAL DEBUG" will helpful to detect the external debugger connected to the launchpad.

    The below is the actual debugger connector in launchpad

    If you see by default a pull-up resistor is connected to the EXTERNAL DEBUG pin of the controller. So, if no external debugger connected to this connector then the controller will read 3.3v on the EXTERNAL DEBUG pin, so it assumes that there is no external debugger connected to the board and in this case the JTAG lines of the controller will be controlled by internal debugger IC TM4C129ENCPDT placed on the launchpad

    In this case the user can debug the board by connecting USB cable at J13 USB connector using internal debugger

    If customer connects an external debugger, then EXTERNAL DEBUG i.e. 8th pin of the J1 connector will be connected with the 8 th pin of the External debugger i.e. GND

    So now the controller will read a logic-0 on the pin EXTERNAL DEBUG and assumes that a external debugger is connected to the launchpad now the control of JTAG lines will be controlled by external debugger.

    --

    Thanks & regards,
    Jagadish.

  • 0 in reply to jagadish gundavarapu
    TI__Genius 13959 points

    Hi Jagadish,

    Thanks for these information, have helped us better understand the communication between the external debugger and TM4C129ENCPDT.

    However, we still have some concerns about the TEST pin. As you can see in the attached picture:


    the RM46L852 have got the following TEST signals: TEST, nTRST, RTCK, TCK, TDI, TDO and TMS. Therefore, we do not understand why the TEST pin does not appear in the schematic of the LAUNCHXL2-RM46.

    We want to know if this pin is relevant for the testing and debugging process and if this pin is not used what are the reasons. For example, in the MSP430F5529, concretely for the Launchpad MSP-EXP430F5529LP, the TEST pin is fundamental to do the debugging process both internal and external debugger.

    Regards,
    Archie A.

  • 0 in reply to ArTzy
    TI__Mastermind 39295 points

    Hi Archie,

    We recommend pulling this TEST pin down either via a resistor or directly shorting to ground.

    Please refer below highlighted sentence

    (+) TMS570LC4357: AJSM Bypass using TEST Pin - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

    --

    Thanks & regards,
    Jagadish.

  • 0 in reply to jagadish gundavarapu
    TI__Genius 13959 points

    Hello Jagadish,

    Good day and thanks for your response.

    We can understand that the TEST pin is not used in the RM46x microcontroller and it must be in pull-down. Therefore, the debugging process is performed via the RTCK, TCK, TDI, TDO and TMS signals. Is this correct?

    Regards,
    Archie A.

  • +1 in reply to ArTzy
    TI__Mastermind 39295 points
    ArTzy said:
    We can understand that the TEST pin is not used in the RM46x microcontroller and it must be in pull-down. Therefore, the debugging process is performed via the RTCK, TCK, TDI, TDO and TMS signals. Is this correct?

    Yes, you are correct.