NXP Semiconductors KE1xF Series, Reference Manual, Page: 652 / 1483

25.2.3.1 Partial Stop
Partial Stop is a clocking option that can be taken instead of entering Stop mode and is
configured in the SMC Stop Control Register (SMC_STOPCTRL). The Stop mode is
only partially entered, which leaves some additional functionality alive at the expense of
higher power consumption. Partial Stop can be entered from either Run mode or VLP
Run mode.
When configured for PSTOP2, only the core and system clocks are gated and the bus
clock remains active. The bus masters and bus slaves clocked by the system clock enter
Stop mode, but the bus slaves clocked by bus clock remain in Run (or VLP Run) mode.
The clock generators in the SCG and the on-chip regulator in the PMC also remain in
Run (or VLP Run) mode. Exit from PSTOP2 can be initiated by a reset, an asynchronous
interrupt from a bus master or bus slave clocked by the system clock, or a synchronous
interrupt from a bus slave clocked by the bus clock. If configured, a DMA request (using
the asynchronous DMA wakeup) can also be used to exit Partial Stop for the duration of a
DMA transfer before the device is transitioned back into PSTOP2.
Any AWIC interrupt can be used as a wake up source from Stop (normal Stop and VLPS)
mode. See
Table 25-5 for all the available wake up source. Besides waking up the CPU
from Stop mode, the DMA can perform data transfer while retaining the CPU in Low
Power mode.
25.2.3.2 DMA Wakeup
The DMA can be configured to wake the device on a DMA request whenever it is placed
in Stop mode. The wake-up is configured per DMA channel and is supported in Compute
Operation, PSTOP, STOP, and VLPS low power modes.
When a DMA wake-up is detected in PSTOP, STOP or VLPS then the device will initiate
a normal exit from the low power mode. This can include restoring the on-chip regulator
and internal power switches, enabling the clock generators in the SCG, enabling the
system and bus clocks (but not the core clock) and negating the stop mode signal to the
bus masters and bus slaves. The only difference is that the CPU will remain in the low
power mode with the CPU clock disabled.
During Compute Operation, a DMA wake-up will initiate a normal exit from Compute
Operation. This includes enabling the clocks and negating the stop mode signal to the bus
masters and bus slaves. The core clock always remains enabled during Compute
Operation.
Power Modes Description
Kinetis KE1xF Sub-Family Reference Manual, Rev. 4, 06/2019
652 NXP Semiconductors