The nRF5340 DK supports programming and debugging external boards with an nRF51, nRF52, and nRF53 Series System on Chip (SoC), or the nRF91 Series System in Package (SiP).
The interface MCU on the nRF5340 DK runs SEGGER J-Link Onboard (OB) interface firmware. It is used to program and debug the application firmware of the nRF5340 SoC, by default.
To program/debug an external board instead, connect to the Debug out connector (P19) using a 10-pin cable or use P20 for custom connection.
Note: It is recommended to power the external board
separately from the DK. The voltage on the external board
must match that of the DK. When the DK is powered through the USB connector, the voltage
is 3V.
Figure 1. Debug output connectors
