Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual page 297

Reference Manual
CMU - Clock Management Unit
EM0/EM1 Entry
&&
CMU_HFXOCTRL.AUTOSTARTSELEM0EM1 = 0 RAC wake-up with CMU_HFXOCTRL.AUTOSTARTRDYSELRAC = 1
HFXO ready Automatic switch to HFXO and disable of HFRCO
HFRCO selected
CMU_STATUS.HFRCORDY
CMU_STATUS.HFRCOENS
CMU_HFCLKSTATUS.HF = HFRCO
CMU_STATUS.HFXORDY
CMU_STATUS.HFXOENS
CMU_HFCLKSTATUS.HF = HFXO
HFCLK
HFRCO
HFXO
Figure 11.10. CMU Automatic HFXO startup/selection while HFRCO started/selected
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