To enter HSRUN mode, set RUNM=HSRUN. Before increasing clock frequencies, the
PMSTAT register should be polled to determine when the system has completed entry
into HSRUN mode. To reenter normal RUN mode, clear RUNM. Any reset will also
clear RUNM and cause the system to exit to normal RUN mode after the MCU exits its
reset flow.
15.4.4 Wait modes
This device contains two different wait modes which are listed here.
• Wait
• Very-Low Power Wait (VLPW)
15.4.4.1 WAIT mode
WAIT mode is entered when the ARM core enters the Sleep-Now or Sleep-On-Exit
modes while SLEEDEEP is cleared. The ARM CPU enters a low-power state in which it
is not clocked, but peripherals continue to be clocked provided they are enabled. Clock
gating to the peripheral is enabled via the SIM module.
When an interrupt request occurs, the CPU exits WAIT mode and resumes processing in
RUN mode, beginning with the stacking operations leading to the interrupt service
routine.
A system reset will cause an exit from WAIT mode, returning the device to normal RUN
mode.
15.4.4.2 Very-Low-Power Wait (VLPW) mode
VLPW is entered by the entering the Sleep-Now or Sleep-On-Exit mode while
SLEEPDEEP is cleared and the MCU is in VLPR mode.
In VLPW, the on-chip voltage regulator remains in its stop regulation state. In this state,
the regulator is designed to supply enough current to the MCU over a reduced frequency.
To further reduce power in this mode, disable the clocks to unused modules by clearing
the peripherals' corresponding clock gating control bits in the SIM.
VLPR mode restrictions also apply to VLPW.
When an interrupt from VLPW occurs, the device returns to VLPR mode to execute the
interrupt service routine.
Functional description
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
354
Freescale Semiconductor, Inc.