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PXA300 Processor and PXA310 Processor
Vol. I: System and Timer Configuration Developers Manual
Doc. No. MV-TBD-00 Rev. A
CONFIDENTIAL
Copyright © 12/13/06 Marvell
Page 252
Document Classification: Proprietary Information
December 13, 2006
Not approved by Document Control. For review only.
The BPMU watches for wake-up events that are qualified with the enabled wake-ups preprogrammed by the core
prior to entering D3 state and sent to the BPMU. However, the receiving PMU takes up to a specified amount of
time to acknowledge the GPIO wake-up edge and begin the wake-up sequence. Refer to the PXA300 and
PXA310 Processor Electrical, Mechanical, and Thermal Specification for this time duration.
If the application subsystem is in D3 state and nBATT_FAULT is asserted, a wake-up event is generated to the
BPMU, followed by an interrupt to the core if the BIE bit is set to 1. Software must handle the interrupt by
entering D4 (the MPMU is entering S3) state using a software-driven entry sequence. If nBATT_FAULT is
asserted and the BIE bit is set to 0, the MPMU automatically transitions to S3 (with the application subsystem
entering D4) state with the result being the complete loss of state information in the application subsystem. In
this case, no interrupt is sent to the core.
Exiting D3 State
D3 state exits to D0 state with the assertion of any of the following wake-up events:
•
Assertion of any enabled D3 state wake-up event selected in the
“Application Subsystem Wake-Up from D3
. The wake-ups enabled in
“Application Subsystem Wake-Up from D3 Enable
are designed to bring the processor from D3 to D0 application subsystem state.
Wake-ups controlled by the PWER register in the MPMU are designed to transfer the MPMU from S2 to S0.
This implies that if the part is in S2/D3, then both AD3ER and PWER registers need to have a wake-up
enabled to return to S0/D0.
•
Assertion of nBATT_FAULT while BIE bit is set to 1 results in exiting to D0 state to execute the battery
fault handler software routine. If nBATT_FAULT is asserted but the BIE bit is clear, the MPMU
automatically transitions to S3 (with the application subsystem entering D4) state without providing a
wake-up event to the BPMU to exit D3 state. Refer to the Services Unit Power Manager Unit section for
details nBATT_FAULT operation.
The following occurs after the assertion of a D3-state wake-up event:
•
BPMU initiates a voltage-change sequence for VCC_APPS and VCC_SRAM for D0 state. The PWR_I
2
C
module in the services unit sends PWR_I2C commands to the external regulator to control the VCC_APPS
and VCC_SRAM power supplies.
•
The MPMU waits the number of timekeeping oscillator cycles specified by the PWR_DEL bits in the Power
Management Unit General Configuration register (PCFR) if PCFR[SWDD] is clear before continuing the
wake-up sequence. If PCFR[SWDD] is set, the MPMU exits the PWR_DEL delay count when VCC_APPS
and VCC_SRAM voltages are detected and continues the wake-up sequence.
•
If disabled, the MPMU enables the processor oscillator.
•
When exiting D3 state, if any of the D3 state unit operation bits are clear, the power for that unit is restored.
•
The units selected by the D3 state unit operation bits exit a low-power state.
•
The ring oscillator is enabled and used as a temporary clock source for the core and application-subsystem
peripherals, if PCCE bit in
Section 7.4.1, “Application Subsystem Clock Configuration Register (ACCR)”
set.
•
Unless specifically disabled, the core PLL is enabled and reprogrammed with the corresponding values in
the
Section 7.4.1, “Application Subsystem Clock Configuration Register (ACCR)”
. Unless specifically
disabled, the system PLL is enabled.
•
Clocks are restarted for units selected by the CKEN bits in the D0CKEN register, refer to
Mode Clock Enable Register A (D0CKEN_A)”
and
Section 7.4.5, “D0 Mode Clock Enable Register B
.