Footprint provision is available on-board for an external 12 MHz crystal oscillator. The external oscillator (XOSC) acts as a clock source for generic clock generators. Configure the XOSC using the generic clock controller.
At Reset, disable the XOSC and use the XIN (PA14)/XOUT (PA15) pins as GPIO pins with other peripherals in the system. The operating mode determines the GPIO usage after enabling the XOSC. In the Crystal Oscillator mode, OSCCTRL controls the XIN and XOUT pins and overrides the GPIO functions on both of the pins.