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Before entering LLS mode, the user should configure the low-leakage wakeup (LLWU)
module to enable the desired wakeup sources. The available wakeup sources in LLS are
detailed in the chip configuration details for this device.
After wakeup from LLS, the device returns to normal RUN mode with a pending LLWU
module interrupt. In the LLWU interrupt service routine (ISR), the user can poll the
LLWU module wakeup flags to determine the source of the wakeup.
NOTE
The LLWU interrupt must not be masked by the interrupt
controller to avoid a scenario where the system does not fully
exit stop mode on an LLS recovery.
An asserted RESET pin will cause an exit from LLS mode, returning the device to
normal RUN mode. When LLS is exiting via the RESET pin, the PIN and WAKEUP bits
are set in the SRS0 register of the reset control module (RCM).
14.4.5.4 Very-Low-Leakage Stop (VLLSx) modes
This device contains these very low leakage modes:
• VLLS3
• VLLS2
• VLLS1
VLLSx is often used in this document to refer to all of these modes.
All VLLSx modes can be entered from normal RUN or VLPR modes.
The MCU enters the configured VLLS mode if:
• In Sleep-Now or Sleep-On-Exit mode, the SLEEPDEEP bit is set in the System
Control Register in the ARM core, and
• The device is configured as shown in Table 14-7.
In VLLS, the on-chip voltage regulator is in its stop-regulation state while most digital
logic is powered off.
Before entering VLLS mode, the user should configure the low-leakage wakeup (LLWU)
module to enable the desired wakeup sources. The available wakeup sources in VLLS are
detailed in the chip configuration details for this device.
After wakeup from VLLS, the device returns to normal RUN mode with a pending
LLWU interrupt. In the LLWU interrupt service routine (ISR), the user can poll the
LLWU module wakeup flags to determine the source of the wakeup.
Functional description
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
312
Preliminary
Freescale Semiconductor, Inc.
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