nRF52832 can use an
optional 32.768 kHz crystal (X2) for higher accuracy and lower average power
consumption.
On the
nRF52 PDK, P0.00 and P0.01 are by default used for the 32.768 kHz crystal and are not available as
a GPIO on the connectors.
Important: 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
Configuring P0.00 and P0.01 for reference.
Figure 1. Configuring P0.00 and P0.01
Figure 2. 32.768 kHz crystal and SB1 to SB4 schematic