The PIC18F56Q35 Curiosity Nano Board has a 32.768 kHz crystal mounted. The crystal is not connected to the target MCU by default, as the GPIO pins are routed to the edge connector.
Figure 7-3. 32.768 kHz Crystal Block Diagram
Note: The 32.768 kHz crystal on the PIC18F56Q35 Curiosity Nano is included for use and testing with the PIC18F56Q35 External 32.768 kHz Oscillator (XOSC32K) configured in High-Power mode.
Table 7-3. Crystal Connections
PIC18F56Q35 Pin
Description
Default Connection
RC0
Crystal output, SOSCO
Edge connector
RC1
Crystal input, SOSCI
Warning: Always disconnect the board from all power sources before making any hardware modifications.
How to Connect the Crystal to the Target Device
Disconnect the two I/O lines routed to the edge connector by cutting the two cut straps on the bottom side of the board, J108 and J109.
Connect the two I/O lines to the crystal by soldering a blob onto each circular solder point on the top of the board, J110 and J111.
Figure 7-4. 32.768 kHz Crystal Overview
Info: The 0Ω series resistor, R110, may be replaced with any suitable resistor to limit the drive strength of the crystals. If no resistor is required, leave the resistor in place.
The 32.768 kHz crystal has a cut strap (J112), which can be used to measure the oscillator safety factor. This is done by cutting the strap and adding a 0402 SMD resistor across it. The AN2648 application note from Microchip contains more information about oscillator allowance and safety factors.
The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.
