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PXD10RM Datasheet, PDF (1000/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller | |||
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Each power domain which is powered down is held in a reset state. Read/write accesses to peripherals in
those power domains will result in a transfer error.
29.4.4 Mode Transitions
On a mode change requested by the MC_ME, the MC_PCU evaluates the power configurations for all
power domains. It compares the settings in the PCU_PCONFn registers for the new mode with the settings
for the current mode. If the configuration for a power domain differs between the modes, a power state
change request is generated. These requests are handled by a finite state machine to ensure a smooth and
safe transition from one power state to another.
29.4.4.1 DRUN, SAFE, TEST, RUN0â¦3, HALT, and STOP Mode Transition
The DRUN, SAFE, TEST, RUN0â¦3, HALT, and STOP modes allow an increased power saving. The
level of power saving is software-controllable via the settings in the PCU_PCONFn registers for power
domain #2 onwards. The settings for power domains #0 and #1 can not be changed. Therefore, power
domains #0 and #1 remain connected to the power supply for all modes beside STANDBY.
Figure 29-6 shows an example for a mode transition from RUN0 to HALT and back, which will result in
power domain #2 being powered down during the HALT mode. In this case, PCU_PCONF2.HALT is
programmed to be â0â.
When the MC_PCU receives the mode change request to HALT mode, it starts its power-down phase.
During the power-down phase, clocks are disabled and the reset is asserted resulting in a loss of all
information for this power domain.
Then the power domain is disconnected from the power supply (power-down state).
new mode
requested by ME
RUN0
HALT
RUN0
PSTAT.PD2
voltage in
power domain #2
current mode
RUN0
HALT
RUN0
Notes:
power-up state power-down
phase
power-down state
Not drawn to scale; PCONF2.RUN0 = 1; PCONF2.HALT = 0
power-up phase
power-up state
Figure 29-6. MC_PCU Events During Power Sequences (non-STANDBY mode)
When the MC_PCU receives a mode change request to RUN0, it starts its power-up phase if
PCU_PCONF2.RUN0 is â1â. The power domain is re-connected to the power supply, and the voltage in
29-8
PXD10 Microcontroller Reference Manual, Rev. 1
PreliminaryâSubject to Change Without Notice
Freescale Semiconductor
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