Table 7-5 lists the different power modes and the expected states for each power domain.
Table 7-5 IPUx Subsystem Power Modes | | Activity | Power Status |
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| Functional Domain | Core | IPUx subsystem | PD_DSP Power Domain | PD_COREAON Power Domain |
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| Modules included | IPUx_C0 | IPUx_C1 | IPUx_WUGEN | | |
Power modes | Active | Active | Active | Active | ON | ON |
IPUx_C0 idle | Idle | Active | Active | ON | ON |
IPUx_C1 idle | Active | Idle | Active | ON | ON |
Core standby | Idle | Idle | Active | ON | ON |
Full idle | Idle | Idle | Idle | ON | ON |
CSWR | Idle | Idle | Idle | ON/LOWV | ON/LOWV |
OSWR | Idle | Idle | Idle | RET | ON |
Power off | Idle | Idle | Idle | OFF | OFF |
Table 7-6 lists the power mode transitions in the IPUx subsystem.
Table 7-6 Power Mode Transitions | Active | IPUx_C0 Idle | IPUx_C1 Idle | Standby | Full-Idle | Retention | Power Off |
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Active | | WFE/WFI instruction | WFE/WFI instruction | | | | |
IPUx_C0 idle | Events/ interrupts | | | Deep sleep | | | |
IPUx_C1 idle | Events/ interrupts | | | Deep sleep | | | |
Standby | Wake-up IRQ | | | | L1/L2/ IPUx_WUGEN functional domain idle | | |
Full idle | Wake-up IRQ | | | Wake-up (through interconnect) | | PRCM module | PRCM module |
CSWR/OSWR | | | | | PRCM module or wakeup | | PRCM module |
Power off | | | | | PRCM module or wakeup | PRCM module | |
The different power modes and their features are:
- Active mode: All function domains are operative.
- IPUx_C0 and IPUx_C1 idle mode:
- Only the CPU core is idled (when running WFE/WFI instructions).
- Only one Cortex-M4 core can be in this mode. Interrupts or events can waken the core.
- Can go into sleep or deep-sleep mode. Potentially, both cores can be in sleep mode.
- When both cores are in deep-sleep mode, a standby request is sent to the PRCM module.
- Software must ensure that all IPUx_UNICACHE
background operations (for example, maintenance) are complete before the
PRCM module asserts an IdleReq.
- Core standby mode
- Both cores in the CORE functional domain are in idle mode (an interrupt cannot wake up either of the cores).
- The PRCM module must have acknowledged its acceptance by an MWait signal.
- After this handshake, all power management is under the control of the PRCM module.
- Full-idle mode:
- The IPUx subsystem functional domain is also idled.
- After coming to this mode, power states can be moved deeper.
- Retention mode:
- The voltage of the logic supply is lowered to reduce static power consumption by leakage current. The logic power switch in the PD_IPU power domain is still closed (ON); thus, all logic states are retained.
- L1 and/or L2 memories can go independently into retention depending on the settings done at the PRCM level.
- Power off mode:
- The voltage source is shut down. The logic states, including the retention logic, are lost.
- The IPUx_WUGEN is not operating and only the PRCM module can trigger the IPUx subsystem wakeup.
- Reset must be applied to the IPUx subsystem to restart the two Arm Cortex-M4 processors and the memory subsystem.