nRF52840 DK v1.0.0

32.768 kHz crystal

The nRF52840 System on Chip (SoC) can use an optional 32.768 kHz crystal (X2) for higher accuracy and lower average power consumption.

On the nRF52840 Development Kit (DK) board, P0.00 and P0.01 are used for the 32.768 kHz crystal by default and are not available as GPIO on the connectors.
Note: When using ANT™/ANT+™, the 32.768 kHz crystal (X2) is required for correct operation.
If P0.00 and P0.01 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 the following figure for reference.
Figure 1. Configuring P0.00 and P0.01
PCA10056 board: Configuring P0.00 and P0.01
Figure 2. 32.768 kHz crystal and SB1SB4
Schematic: 32.768 kHz crystal and SB1-SB4