4.2.1 Crystals

The SAM G55 Xplained Pro kit contains a 32kHz crystal mounted on it along with a footprint for a second crystal. The crystal circuit has a cut-strap next to it which can measure the oscillator safety factor. This is performed by cutting the strap and adding a resistor across the strap. More information about oscillator allowance and safety factor can be found in application note AVR4100.

Table 4-5. External 32.768kHz Crystal
Pin on SAM G55Function
PA07XIN32
PA08XOUT32

The additional crystal's pins are shared with the TWI lines in EXT3. Remove the 0Ω resistors R307 and R306 before mounting this crystal.

Table 4-6. Footprint for Additional Crystal
Pin on SAM G55Function
PB09XIN
PB08XOUT