[SOLVED] Why I get Vtref = 0.000V when I debugged nrf52832 with J-Link debugger

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  • [SOLVED] Why I get Vtref = 0.000V when I debugged nrf52832 with J-Link debugger

    Hello, I am debugging my custom board with J-link debugger. The board has nRF52832 as MCU and the power supply is 2.5V. When I debugged the nRF52832 with J-Link, it failed and the error showed " Vtref = 0.000V". But I check the Voltage on the debug port and the voltage is 2.5V. I followed the manual and use the 20-pin connect cable.

    Pin 1 connected to VCC on board. SWDIO connected to Pin 26 of nRF52832, SWCLK connected to Pin 25 of nRF52832, and GND to GND on board.
    The error is shown below.
    How can I debug the problem? Thanks
    • error1.jpg

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    • pin.png

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  • I just connect the Pin1 and Pin4 of the cable to a cell battery which voltage is 3.3V. But the J-Link Debugger still found Vtref = 0.000V. So wired. Do I need to buy some cable for SWD interface?
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    • WeChat Image_20201116035656.jpg

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  • Hi,

    At least on the photo, you have NOT connected the battery to pin 1.
    Pin 1 is indicated by the BLUE wire on the cable.
    Maybe that‘s also the problem on your custom board wiring: Wrong direction of the debug connector...