Hardware description
Figure 14: I/O expander schematic
Important:
SW debouncing should not be needed when using the I/O expander. Each button on
the nRF52 Preview Development Kit board is equipped with a debouncing filter.
6.6 32.768 kHz crystal
nRF52832 can use an optional 32.768 kHz crystal (X2) for higher accuracy and lower average power
consumption.
On the nRF52 Preview Development Kit board, 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
Figure 15:
Configuring P0.00 and P0.01
on page 20 for reference.
Figure 15: Configuring P0.00 and P0.01
4397_497 v1.2
20