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PRCM Functional Description
Software must wait for the I/O daisy chain to complete before it transitions the PER domain to a
nonfunctional state. This is done by polling a dedicated status bit in the PRCM module
(PRCM.
[16] ST_IO_CHAIN). This status bit must be cleared by software when the bit is
read to 1.
The I/O wake-up scheme in each pad is disabled through the I/O daisy chain:
•
The
I/O
wake-up
scheme
is
disabled
by
programming
the
dedicated
register
(PRCM.
[16] EN_IO_CHAIN) in the PRCM module.
•
The
global
I/O
wake-up
enable
bit
is
disabled
by
programming
a
dedicated
register
(PRCM.
[8] EN_IO) in the PRCM module.
•
The I/O wake-up scheme is disabled by triggering the I/O daisy chain control (Wu clock) by writing 1 in
a dedicated register (PRCM.
[8] ST_IO) in the PRCM
This bit is also used to log the source of the I/O wakeup. Writing 1 in this register clears this bit to 0.
3.5.7.3
CORE Power Domain Off-Mode Sequences
The I/O pad wake-up scheme can be activated to detect wake-up events when the CORE power domain
is switched to inactive, retention, or off state. The off state sequences for the CORE power domain include
the sequence for going from on state to retention or off power state (while enabling the I/O pad wake-up
scheme), and then switching back to the on power state (while disabling the I/O pad wake-up scheme) on
an I/O wake-up event.
3.5.7.3.1 Sleep Sequences (Transition From On to Retention/Off)
When the CORE power domain is in RETENTION state, the logic is switched off, its context is saved by
the RFFs in the modules, and the memory blocks are retained. In OFF state, however, the logic and
memories are switched off, and the RFFs are not saved.
NOTE:
If the PER power domain is kept on while the CORE power domain is in RETENTION state,
all I/O wake-up enable (EVT_EN signals) signals to the I/O pads related to the PER power
domain inputs must be disabled (by clearing the CONTROL.CONTROL_PADCONF_<
IOpad>[14] WAKEUPENABLE bit in the SCM). in this case, wake-up events are generated
by the PER domain and not through the daisy chain.
For information about the SCM, see
, System Control Module.
The following sequence is used to go from ON to RETENTION or OFF state:
1. Software sets the PRCM.
[16]
EN_IO_CHAIN bit to enable the I/O pad wake-up scheme.
2. The MPU initiates the sleep sequence. When all conditions are met, the CORE power domain clocks
are shut down. At this stage, most of the pads are inactive, but some, such as the PER and DSS
power domains, can stay active.
3. The PRM initializes and resets the I/O wake-up detection scheme and saves all RFFs. Its CORE
power domain output is isolated from the I/O pads.
4. The PRM switches the CORE power domain to RETENTION/OFF power state. The I/O configuration is
saved on wake-up power domain registers; see
, Save-and-Restore Mechanism, in
, System Control Module, for more information.
5. The PRM waits for a wake-up event from the daisy chain. Other possible wake-up sources can be a
wake-up event from a module in the wake-up power domain or from a global warm reset.
NOTE:
When the CORE power domain is in RETENTION state, VDD2 voltage must be at retention
or on voltage level to maintain stable CORE power domain output values to the I/Os.
393
SWPU177N – December 2009 – Revised November 2010
Power, Reset, and Clock Management
Copyright © 2009–2010, Texas Instruments Incorporated
Содержание OMAP36 Series
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Страница 1084: ...1084 IVA2 2 Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1990: ...1990 2D 3D Graphics Accelerator SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2334: ...2334 Memory Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
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Страница 2868: ...2868 HDQ 1 Wire SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2974: ...2974 UART IrDA CIR SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3054: ...3054 Multichannel SPI SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3462: ...3462 MMC SD SDIO Card Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3508: ...3508 General Purpose Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3584: ...3584 Initialization SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3648: ...3648 Debug and Emulation SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...