(UART) Log Output Through Debug Out

[A Knecht]

Hi I have an external board featuring an nRF52832 connected to the nRF52DK via the Debug Out port on the DK and a 6 pin connector on the external board. I can program the external MCU just fine, but I cannot read debug output that I'm logging via UART. What do I need to do to get this to work?

[endnode]

For UART you need separate wires (typically just one for Tx is fine for beginning). On nRF5x DK boards there are certain PINs from nRF5x target on the board connected to ATMEL companion chip with SEGGER J-Link OB (or mbed) FW which forwards it over USB as emulated serial port so you can simply connect that PIN from your external board to the UART Tx PIN (it's P0.06 according to the documentation) on nRF52 DK and you should be fine. Just be sure that internal target on nRF52 DK is erased so it doesn't interfere with your external input...

[endnode]

You don't have any PIN on your external board available on some debug header? That might look like a mistake now;) Never mind, there is a way to switch P0.21 from nRESET to standard GPIO or P0.18 from SWO to GPIO so if you have one of these connected on your 6-PIN header then reconfigure it in your FW, redirect UART Tx to proper number and then on nRF52 DK side wire proper link instead of JTAG/SWD (or P20 external debug header if you use that) to P0.06.