20.9.1 Wait Mode

When the system is in Wait mode, all clocks of the system except MD_SLCK are stopped. The source clock of all MCKx must be set to the main clock, and the source of the main clock must be set to main RC.

Prior to instructing the device to enter Wait mode:

Note: The sequence below only relates to the PMC. For the complete sequence to enter Wait mode, see “Wait Mode” in the section “Power Supply and Power Control”.
  1. Select Main RC as the source of MAINCK by configuring CKGR_MOR.MOSCSEL to ‘0’
  2. Select MAINCK as the source of all MCKx by configuring PMC_CPU_CKR.CSS to ‘1’ and PMC_CPU_CKR.CPCSS to ‘1’.
  3. Disable the PLL if enabled and disable the main crystal oscillator by setting CKGR_MOR.MOSCXTEN to ‘0’.
  4. Wait for two SLCK clock cycles.
  5. Clear the internal wake-up sources.
  6. Verify that none of the enabled external wake-up inputs (WKUP) hold an active polarity.

The system enters Wait mode by setting CKGR_MOR.WAITMODE. The PMC registers must not be accessed immediately after this access.