Sony CXD5602 User Manual page 156

PMU (Power Management Unit)-32 shows the control flow diagram.
Control Overview

Sleep control
The Application Processor requests Sleep (PWD_APP_DSP "OFF") control to the System and I/O Processor.
After the Application Processor has made this request, it enters WFI state. The System and I/O Processor
then confirms that the Application Processor has entered WFI state, and performs OFF control of the
PWD_APP_DSP.

Wakeup control
Wakeup occurs as a result of an interrupt to the Application Processor. However, the Application Processor
is in Sleep, and cannot receive the interrupt nor perform ON control of the PWD_APP_DSP. Therefore,
during Sleep, the System and I/O Processor receives the interrupt instead, and performs ON control of the
PWD_APP_DSP.
Sleep (PWD_APP_DSP=OFF) Control Flow

Control of Application Processor side
Since Sleep control is not performed during the operation of the Application Processor, the interrupt is
masked and the Application Processor enters WFI state.
1. Mask all interrupts made to the Application Processor.
INT_EN*=0
For details on the interrupt mask INT_EN*, refer to Section 3.3.2.
2. Request Sleep (PWD_APP_DSP "OFF") control to the System and I/O Processor.
3. Issue WFI command.

Control of System and I/O Processor side (reference)
The OFF request of the PWD_APP_DSP is received from the Application Processor, and the control starts.
1. The WFI monitor register (DSP_SLEEPING) of the Application Processor is polled, and the change to
WFI state is confirmed.
2. The PWD_APP_DSP is turned OFF (Refer to Section 3.4.4.1 for Basic flow of power supply control).
3. Cancel the interrupt mask of receiving the interrupt on the Application Processor's behalf.
The following is the setting for using SYDMAC[0] as the Wakeup trigger.
INT_EN3.SYDMAC[0]=1
Wakeup (PWD_APP_DSP=ON) Control Flow
Wakeup starts when the interrupt is received. As an example, the following describes the flow when Wakeup is
performed using the interrupt INT_CAUSE3.SYMAC[0] as the trigger.

Control of the System and I/O Processor side
1. Confirm INT_CAUSE3.SYMAC[0]=1
2. Interrupt mask
INT_EN3.SYDMAC[0]=0
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CXD5602 User Manual