Silicon Labs EFM32: How do I configure the pins when using an external oscillator?

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Silicon Labs EFM32: How should the pins be set when using an external oscillator?

EFx32

Use HFXTAL_N when using an external oscillator as HFXO. Pin setting (explicitly using Pin XXX as NFXTAL_N) is unnecessary, so the default (Pinmode = disable) is fine.
Below is a sample code. The concept is the same for LFXO.

For sine wave

/* Use external sine wave for HFXO */
CMU->CTRL |= CMU_CTRL_HFXOMODE_BUFEXTCLK;
/* Enable HFXO as high frequency clock, HFCLK */
CMU_ClockSelectSet(cmuClock_HF,cmuSelect_HFXO);
/* Turn off HFRCO if not required */
CMU_OscillatorEnable(cmuOsc_HFRCO, false, false);

Square wave

/* Use external digital clock for HFXO */
CMU->CTRL |= CMU_CTRL_HFXOMODE_DIGEXTCLK;
/* Enable HFXO as high frequency clock, HFCLK */
CMU_ClockSelectSet(cmuClock_HF,cmuSelect_HFXO);
/* Turn off HFRCO if not required */
CMU_OscillatorEnable(cmuOsc_HFRCO, false, false);

For settings when using an external crystal, see another topic (How should I set the pins when using an external crystal?).

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