Standby and Wakeup

Block Diagram

The following figure shows the standby and wakeup block diagram.
Figure 1. Standby and Wakeup Block Diagram

Entering Standby Mode

To enter standby mode, only Always-On (AON) modules should be working, including PMU, RTC, and GMAC.

  1. CPU controls PMIC via I2C, with VDD18_HDMI, MIPITX, and MIPIRX powered off.

  2. CPU controls PMIC or the power switches in MIPITX and RX via I2C, with DD09_MIPITX and MIPIRX powered off, to which either internal or external power supplies can be connected. When internal power supplies are fed, the 2 pins can be switched on and off independently.

  3. CPU switches off all digital IP except for CPU itself and SYSTOP by configuring PMU power-down sequence.

  4. To configure standby wakeup source registers, the following three wakeup methods are supported: Wake up via RTC, via GMAC0, and via GPIO3.

  5. When the CPU switches off itself and SYSTOP by configuring the PMU power-down sequence, PMU could drag down or close the TOP power supplies (Orange pins in the figure: Power Up Sequence) via GPIO2.

Waking Up from Standby Mode

To wake up from standby mode:

  1. Wakeup via RTC: RTC automatically switches on CPU, SYSTOP, and the TOP power supplies (Orange pins in the figure: Power Up Sequence) by dragging up GPIO2. System will follow requirements to switch on other power supplies.

    Note:

    • The control signal from GPIO2 to PMIC is active only when RESETN is high, otherwise, the signal is de-activated.

    • Use PMU to control the ON/OFF of the PMIC, a low-EN 3-state switch can be added.

  2. Wakeup via Remote Ethernet: The remote GMAC0 sends interrupts to PMU to wake up CPU, SYSTOP, and the TOP power supplies (Orange pins in the figure: Power Up Sequence) by dragging up GPIO2. System will follow requirements to switch on other power supplies.

  3. Wakeup via GPIO: Press the button to initiate high-level pulses via GPIO3, and trigger PMU to wake up CPU, SYSTOP, and the TOP power supplies (Orange pins in the figure: Power Up Sequence) by dragging up GPIO2. System will follow requirements to switch on other power supplies.