4.3.3 Crystals

The SAMC21N Xplained Pro kit contains one mounted 32.768kHz crystal and a footprint for higher frequency crystals that can be used as clock sources for the SAMC21N. The crystals have cut-straps next to them that can be used to measure the oscillator safety factor. This is done by cutting the strap and adding a resistor across the strap. Information about oscillator allowance and safety factor can be found in appnote AVR4100. Information about clock calibration and compensation can be found in appnote AT03155.

Table 4-15. External 32.768kHz Crystal
SAMC21N pinFunctionShared functionality
PA00XIN32-
PA01XOUT32-
Table 4-16. External Crystal Footprint
SAMC21N pinFunctionShared functionality
PA14XINEXT3 and Shield
PA15XOUTEXT3 and Shield