[SOLVED] VTarget = 0.0V but JTAG pin 1 = 3.3V

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  • [SOLVED] VTarget = 0.0V but JTAG pin 1 = 3.3V

    My J-Link EDU is unable to connect with my target processor (an ATSAME54P20). Here's what J-Link Commander reports upon startup:

    Source Code

    1. SEGGER J-Link Commander V6.41a (Compiled Nov 27 2018 14:10:26)
    2. DLL version V6.41a, compiled Nov 27 2018 14:09:51
    4. Connecting to J-Link via USB...O.K.
    5. Firmware: J-Link V9 compiled Oct 25 2018 11:46:07
    6. Hardware version: V9.40
    7. S/N: 269402808
    8. License(s): FlashBP, GDB
    9. OEM: SEGGER-EDU
    10. VTref=0.000V
    12. Type "connect" to establish a target connection, '?' for help
    13. J-Link>
    Display All

    The suspicious part is "VTref=0.000V". But when I measure the voltage on pin 1 of the 20 pin JTAG connector, I see 3.3V. Does this indicate a faulty J-Link? Or are there other things that could cause this?

  • Hello,

    Thank you for your inquiry.
    Such an issue is not known to us. If you measure 3.3 V on Pin 1 J-Link should see it too.
    Are you using the original JTAG cable shipped with J-Link? If yes, do you have another cable to test against?
    Just to be sure could you double check for correct cable orientation?
    segger.com/products/debug-prob…gy/interface-description/

    Should VTref keep showing 0 V no matter what JTAG cable is used it is most likely defective.
    As the references J-Link is out of maintenance for quite a while now we suggest making use of our trade in program:
    segger.com/purchase/trade-in-program/

    Best regards,
    Nino
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