For boards with a standard 10-pin Serial Wire Debug (SWD) connector or a connector that supports a standard 10-pin flat cable, connection to P19 is recommended.
Connect the boards as shown in the following figure.
Figure 1. Connecting an external board to P19
When the interface MCU detects the voltage of the external board on pin 1 (SWD0_VTG) of P19, it programs or debugs the target chip on the external board instead of the onboard nRF9161 System in Package (SiP).
The following figure and table show the P19 pinout.
Figure 2. Debug output connector P19
| Pin number | Signal | Description |
|---|---|---|
| 1 | SELECT | Voltage supply from the external target, used as a select pin for the interface MCU to enable this port |
| 2 | SWDIO | SWD Data Input/Output |
| 3 | GND | Ground |
| 4 | SWDCLK | Serial wire clock line |
| 5 | GND | Ground |
| 6 | SW0 | Serial Wire Output (SWO) line is not used for programming and debugging over SWD |
| 7 | N.C. | Not used |
| 8 | N.C. | Not used |
| 9 | N.C. | Not used |
| 10 | RESET | Reset line |
If you do not have a separate power supply on the external board connected to the Debug out connector P19, the external board can be powered from the onboard DK regulator as follows:
- Short solder bridge SB24 to enable power output on P19.
- Power the DK through the USB connector.
CAUTION:
To avoid damaging your board when SB24 is
shorted, do not connect a separate power supply to the external board and follow the
instructions carefully.
Note: When SB24 is shorted, it is not
possible to program the onboard nRF9161 SiP, the nRF5340
System on Chip (SoC), or to use debug output on P20 even if the
external board is unplugged.