The Debug in connector P18 makes it possible to connect external debuggers when the interface MCU USB cable is not connected or the Development Kit (DK) is in nRF only mode.
For trace, a footprint for a 20-pin connector P25 is available. If trace functionality is required, it is possible to mount a 2x10 pin 1.27 mm pitch surface-mount pin header. To use trace, you must disable flow control on UART_0 by switching Flow Control SW11 for serial port 0 to the OFF position.
Some of the trace pins are by default used for other functionality on the DK. By sliding the TRACE switch SW7 from Def. to Alt., the functionality is moved to other GPIOs. See the following table for more information.
| GPIO | Trace | Default use | Optional GPIO |
|---|---|---|---|
| P0.07 | TRACECLK | UART CTS | P0.04 |
| P1.00 | TRACEDATA[0] | ||
| P0.12 | TRACEDATA[1] | Button 1 | P1.07 |
| P0.11 | TRACEDATA[2] | Button 2 | P1.08 |
| P1.09 | TRACEDATA[3] |
By default, the reference voltage for the debug input and trace is connected to VDD_nRF'. This can be connected to the VDD by cutting SB60 and soldering SB59.