nRF52840 Preview DK v0.9.x

Debug input and Trace

The Debug in connector (P18) makes it possible to connect external debuggers for debugging when the interface MCU USB cable is not connected or the board is in nRF only mode.

Figure 1. Debug input and Trace connectors
Debug input connector (P18) and Trace connector on nRF52840 Preview Development Kit board

For trace, a footprint for a 20-pin connector is available (P25). If trace functionality is required, a 2×10 pin 1.27 mm pitch surface mount pin header can be mounted.

Some of the trace pins are by default used for other functionality on the board. By sliding the Trace switch from Def. to Alt., the functionality is moved to other GPIOs. See the table below.

Table 1. Default and Trace GPIOs
GPIO Trace Default use Optional GPIO
P1.00 TRACEDATA[0]    
P0.11 TRACEDATA[1] Button 1 P1.07
P0.12 TRACEDATA[2] Button 2 P1.08
P1.09 TRACEDATA[3]    

The switching between default and optional GPIO for the signals is controlled by the Trace switch (SW7).