The nRF5340
System on Chip (SoC) can use an optional 32.768 kHz crystal (X2) for
higher accuracy and lower average power consumption.
On the
nRF5340 DK,
P0.00 and
P0.01 are
used for the 32.768 kHz crystal by default and are not available as
General-Purpose Input/Output (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, then the
32.768 kHz crystal can be disconnected and the GPIO routed to the connectors. Cut the solder
bridges on
SB1 and
SB2, and solder
SB3 and
SB4.
See the following figure for reference.
Figure 1. Configuring P0.00 and P0.01
Figure 2. 32.768 kHz crystal and SB1–SB4