User Manual

nRF51 Development Kit User Guide v1.0
Page 20
5.9 Debug input
The debug input, Debug in (P18) connector, enables connection of external debuggers in order to debug
while running on battery or external power supply.
Figure 19 Debug input connector
5.10 Debug output
The nRF51 DK board supports programming and debugging of external boards. To debug an external
board, connect to the Debug out (P19) connector with a 10 pin cable.
Figure 20 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 external board instead of the on-board nRF51422.
Note: The voltage supported by external debugging/programming is 3.0 V.
The P20 also features a debug out connection in order to program shield mounted targets, as for the Debug
out P19 header the Interface MCU will detect the supply voltage on the mounted shield and program/
debug the shield target.
If the Interface MCU detects target power on both P19 and P20 it will default to program/debug the target
connected to P19
P18, Debug in
P19, Debug out
P20