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PRCM Functional Description
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NOTE:
The domain wake-up dependency is a non-transitive property.
If power domain PD1 has wake-up dependency with power domain PD2, the PRCM.PM_WKDEP_PD1. EN_PD2 bit is set to 1, and if
PD2 has wake-up dependency with power domain PD3, the PRCM.PM_WKDEP_PD2. EN_PD3 bit is set to 1.
However, if PD1does not have a direct wake-up dependency with PD3, the PRCM.PM_WKDEP_PD1. EN_PD3 bit is set to 0. If PD1 and
PD2 are in INACTIVE/RETENTION or OFF power state and PD3 is inactive and is woken-up by a wake-up event, PD2 is also woken-up,
but PD1 is not.
Because a power domain can depend on several other power domains, it can broadcast the wake-up signal to each power domain on which it
depends.
A power domain wake-up dependency can either be hardwired (set in the hardware) or programmable through software by configuring the
PM_WKDEP_<domain> register for that power domain. Continuing the example of PD2 as dependent on PD1, setting the PM_WKDEP_PD1.PD2
bit means that when PD2 wakes up, PD1 also wakes up.
The MPU power domain can be wakened only by the IVA2, DSS, USBHOST, PER, CORE-L3, CORE-L4, and WKUP power domains. Similarly,
the IVA2 power domain can be wakened only by the MPU, DSS, USBHOST, PER, CORE-L3, CORE-L4, and WKUP power domains. All wake-up
dependencies of the MPU and the IVA2 power domain are software-configurable.
For the processor power domains (MPU and the IVA2 power domain), when the wake-up dependency with other power domains is
software-programmable (that is, with the USBHOST, PER, CORE, and WKUP power domains), two registers may need be configured:
PM_WKDEP_<domain> and PM_<processor>GROUPSEL_<domain>.
The PM_WKDEP_<domain> register serves only to enable/disable the global wake-up dependency of the processor power domain on these three
power domains. The PM_<processor>GROUPSEL_<domain> register must be configured to enable the particular wake-up event in these domains
that will wake up the processor domain. Thus, the global wake-up dependency for a dependent domain must be enabled so that a wake-up event
can occur, if it has been enabled in the corresponding GROUPSEL register.
For example, if the wake-up dependency of the MPU power domain is to be enabled for a wake-up event from the GPIO2 module of the PER
power domain, the following configuration is required:
•
PRCM.
[13] GRPSEL_GPIO2
•
PRCM.
[7] EN_PER
summarizes the programmable and hardwired wake-up dependencies among the domains.
Table 3-76. Wake-Up Dependencies
Wake-Up Dependency
Power Domain
Clock
MPU
NEON
IVA2
SGX
CAM
DSS
USB
PER
CORE_
CORE_
CORE_
WKUP
Domain
HOST
L3
L4
CM
MPU
MPU
N/A
0
RW
0
0
RW
RW**
RW*
RW*
RW*
0
RW**
NEON
MPU
RW
N/A
0
0
0
0
0
0
0
0
0
0
IVA2
IVA2
RW
0
N/A
0
0
RW
RW**
RW*
RW*
RW*
0
RW*
SGX
SGX
RW
0
RW
N/A
0
0
0
0
0
0
0
RW
364 Power, Reset, and Clock Management
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated
