Flashing nRF52832 using nRF52840 DK

RE: Flashing nRF52832 using nRF52840 DK

Simonr — Mon, 15 Dec 2025 12:43:13 GMT

Hi Kåre

Glad to hear you got to the bottom of it! These configs are indeed necessary if you don't have an external 32.768kHz crystal.

Best regards,

Simon

RE: Flashing nRF52832 using nRF52840 DK

Kaare — Fri, 12 Dec 2025 11:02:41 GMT

Hi Simonr, sorry for the late response

I figured it out. It was in part due to power configurations but also because I didn't include the external 32 kHz crystal. For anybody designing their own custom PCBs and run into the same problem as me I got it to work by adding these two lines to the prj.conf

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

The wiring I used was
Custom PCB - nRF52840 DK
GND - GND detect
SWDIO - SWDIO
SWDCLK - SWDCLK
VDD - VTG

And then I powered my PCB with a battery

RE: Flashing nRF52832 using nRF52840 DK

Simonr — Wed, 03 Dec 2025 13:43:01 GMT

Hi Kåre

How have you powered the external board here? Does it run off a battery, and if so, at what voltage? The nRF52840 won't be able to power your custom board, and it needs to be powered with 3.0V from an external source in order to make sure the DK detects it as connected. If not I assume you're only flashing the onboard nRF52840 SoC with your firmware. You also probably need to make your own board file instead of the nrf52dk/nrf52832 target, since I assume you have a few differences in the board itself from the nRF52832 DK.

See the section on custom board files in the DevAcademy for reference. https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-3-adding-custom-board-support/

Best regards,

Simon

RE: Flashing nRF52832 using nRF52840 DK

Kaare — Tue, 02 Dec 2025 13:51:37 GMT

Sorry, somehow I inserted the same photo twice