The PIC18F47K42 Curiosity Nano board has a footprint for a 32.768 kHz crystal.
The crystal footprint is connected to the PIC18F47K42 by default, but the GPIOs are routed out to the edge connector through open solder straps. The two I/O lines routed to the edge connector are disconnected by default to both reduce the chance of contention to the crystal as well as removing excessive capacitance on the lines when using the crystal. To use the pins RC0 and RC1 as GPIO on the edge connector, some hardware modification is needed. Add a solder blob to the open straps on the bottom side to connect the routing. The crystal should be disconnected when using the pin as GPIO, as this might harm the crystal.
| PIC18F47K42 Pin | Function | Shared Functionality |
|---|---|---|
| RC0 | SOSC0 (Crystal output) | Edge connector |
| RC1 | SOSCI (Crystal input) | Edge connector |