User Manual

nRF51 Development Kit User Guide v1.0
Page 17
5.6 32.768 kHz crystal
nRF51422 can use an optional 32.768 kHz crystal (X2) for higher accuracy and lower average power
consumption. On the DK board, P0.26 and P0.27 are by default used for the 32.768 kHz crystal and are not
available as a GPIO on the connectors.
Note: When using ANT/ANT+, the 32.768 kHz crystal (X2) is required for correct operation.
If P0.26 and P0.27 are needed as normal I/Os the 32.768 kHz crystal can be disconnected and the GPIO
routed to the connectors. Cut the shorting track on SB1 and SB2, and solder SB3 and SB4. See Figure 14 for
reference.
Figure 14 Disconnecting 32.768 kHz crystal and connecting P0.26 and P0.27 to the connectors
Figure 15 32.768 kHz crystal and SB1 to SB4 schematic
SB1 (Cut)
SB2 (Cut)
SB3 (Solder)
SB4 (Solder)
C14
12pF
C13
12pF
X2
32.768kHz
P0.26
P0.27
XL2 XL1
SB3
SB4
SB1
SB2