4.2.3 Crystal
The PIC16F18446 Curiosity Nano board has a 32.768 kHz crystal footprint made for standard 3.2 mm by 1.5 mm surface mount crystals with two terminals.
The crystal footprint is not connected to the PIC16F18446 by default, as the GPIOs are routed out to the edge connector. To use the crystal, some hardware modifications are required. The two I/O lines routed to the edge connector must be disconnected to reduce the chance of contention to the crystal, and to remove excessive capacitance on the lines. This can be done by cutting the two straps on the bottom side of the board, marked RA4 and RA5, as shown in the figure below. Next, solder on a solder blob on each of the circular solder points next to the crystal on the top side of the board, as shown in the figure below.
PIC16F18446 Pin | Function | Shared Functionality |
---|---|---|
RA4 | SOSCO (Crystal output) | Edge connector |
RA5 | SOSCI (Crystal input) | Edge connector |