4.2.3 Crystal
The PIC18F47Q10 Curiosity Nano board has a 32.768 kHz crystal footprint made for standard 3.2 mm by 1.5 mm surface-mounted crystals with two terminals.
- 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
- Disconnect the edge connector by cutting the two cut-straps on the bottom side of the board, marked RC0 and RC1
- Connect the crystal by soldering on a solder blob on each of the circular solder points next to the crystal on the top side of the board, J210 and J211
Figure 4-4 show cut straps and solder points.
The PIC18F47Q10 Curiosity Nano board has been tested with a 7 pF equivalent load capacitance 70 kΩ ESR crystal (VMK3-9001-32K7680000TR) and 5 pF load capacitors. A similar setup is recommended when using a 32.768 kHz crystal with the PIC18F47Q10 Curiosity Nano.
The crystal has a cut-strap next (J209) to it, which can be used to measure the oscillator safety factor. This is done by cutting the strap and adding a 0402 SMD resistor across the strap. More information about oscillator allowance and safety factor can be found in the AN2648 application note from Microchip.
PIC18F47Q10 Pin | Function | Shared Functionality |
---|---|---|
RC0 | SOSCO (Crystal output) | Edge connector |
RC1 | SOSCI (Crystal input) | Edge connector |