(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...

[A Knecht]

P0.18/SWO is connected to SWO on the needle connector and I configured the NRF_LOG_BACKEND_UART_TX_PIN to 18, so I think it is handled on the external board side. I tried to connect SWO on the P20 connector to P0.06 on the DK, but I still don't get any UART logs. What do you advise? When I look at the schema of the DK i see that SWO on P19 is labelled EXT_SWO and SWO on P20 is labelled SH_SWO and both are connected to the debug chip, but don't seem to be directly connected.