The nRF5340 PDK supports programming and debugging external boards with nRF51 Series, nRF52 Series, or nRF53 Series System on Chip (SoC)s. To debug an external board with SEGGER J-Link OB IF, connect to the Debug out connector (P19) with a 10-pin cable.
Figure 1. Debug output connector
When the external board is powered, the interface MCU will detect the supply voltage of the
board and program/debug the target chip on the external board instead of the onboard nRF5340
SoC.
Note: The voltage supported by external debugging/programming
is VDD voltage. Normally, this is 3 V when running from USB, but if the onboard nRF5340 SoC is
supplied from either USB or Li-Ion, the nRF power source switch (SW9) is in either
Li-Po or USB position, and VDD can be set by the nRF5340 firmware. Make sure the voltage level
of the external board matches the VDD of the nRF5340 PDK.
You
can also use P20 as a debug out connection to program shield-mounted targets. For both
P19 and P20, the interface MCU will detect the supply voltage on the
mounted shield and program/debug the target.If the interface MCU detects target power on both P19 and P20, it will by default program/debug the target connected to P19.
If it is inconvenient to have a separate power supply on the external board, the nRF5340 PDK can supply power through the Debug out connector (P19). To enable this, short solder bridge SB47. While SB47 is shorted, it is not possible to program the onboard nRF5340 SoC even if the external board is unplugged.