nRF52832 "unable to connect to the target"


I have an nRF52832 on a custom board. I managed to flash it through JLink and STLinkv2. But suddenly, I wasn't able to communicate to it anymore.

Openocd tells me: "unable to connect to the target".

So I measured all the internal reference voltages at respective pins and they're all okay at 1.28V. External voltage is at 3.3V as expected. The reset pin stays at 1.5V even during the flashing process and doesn't move even a bit, even tho the reset pin is pulled down to ground with a resistor.

Does anyone have an idea what I could be doing wrong and tell me?

Thanks! Best regards Yatekii

  • Hi, the reset pin is active low, which means that when you pull it to ground the chip is in a reset state. The reset pin also has an internal pull-up (13k), so you must remove the external pull-down. I guess that's why you see 1.5V on the pin. You should just leave the reset pin unconnected, or connect it to ground through a button (if you need the pin reset)

    Other things: Maybe you accidentally enabled DCDC without having DCDC components on your custom board.

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