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Services Power Management Unit
Copyright © 12/13/06 Marvell
CONFIDENTIAL
Doc. No. MV-TBD-00 Rev. A
December 13, 2006
Document Classification: Proprietary Information
Page 185
Not approved by Document Control. For review only.
The PWR_CAP<1:0> pins are required to have an external 0.1-
μ
F capacitor connected between them. If a
polarized capacitor is used, the + plate must be connected to PWR_CAP<1>.
8.4.11
Power Management Supply Output (PWR_OUT)
The services unit DC-DC converter requires an external 0.1-
μ
F capacitor connected between the PWR_OUT pin
and ground. This connection is the only allowed connection or load on the PWR_OUT pin. This function is not
optional and must be connected through a 0.1-
μ
F capacitor to ground for guaranteed operation.
8.5
Operation
The MPMU controls the operation of power modes and resets to modules within the services unit as well as the
BPMU. The MPMU also interfaces with the external supply regulator through an I
2
C interface. Control over
these features as well as the clocks to each unit through the clocks units allows the overall power consumption
and performance of the processor to be optimized for particular applications. To provide the above functions, the
MPMU contains these sections:
•
Reset management
•
Power management
•
Voltage management
Each part of the MPMU is described in the sections that follow.
8.6
Reset Management Operation
Reset of the services unit can occur by one of five resets:
•
Power-on reset—An uncompromised, ungated, total and complete reset used when the VCC_BBATT is
powered up. If VCC_BBATT has been powered-on, power-on reset is asserted when VCC_BBATT is
removed or VCC_BBATT drops below 2.4 V, which is the VCC_BBATT minimum voltage (refer to the
PXA300 Processor and PXA310 Processor Electrical, Mechanical, and Thermal Specification for details),
and remains asserted until a positive power-supply assertion is detected on the back-up battery pin
VCC_BBATT . Power-on reset is used by all logic blocks within the services unit and is output to the
application subsystem as part of the system reset.
•
Hardware reset—An uncompromised, ungated, total and complete reset used when absolutely no system
information requires preservation. Hardware reset is used by all logic blocks within the services unit and is
output to the application subsystem as part of the system reset.
•
GPIO reset—Used as an alternative to hardware reset, where an external source can reset the processor
while preserving those registers listed in
and external memory contents. GPIO reset does not reset
the MPMU, PLLs, and certain registers within the RTC. GPIO reset is sent directly to the application
subsystem.
•
S3 low-power state exit reset—Resets the modules that have been powered down in S3 state so that they can
recover properly when power is reapplied. Within the services unit, the processor oscillator, ring oscillator,
PLLs and power manager I
2
C modules are reset by the low-power state exit reset when exiting S3 state. All