2.1.12. Power management

The processor includes several microarchitectural features to reduce energy consumption:

Each CPU supports four levels of power management:

Run mode

This mode is the normal mode of operation where all of the functionality of the CPU is available.

Standby mode

This mode disables most of the clocks of the CPU, while keeping the device powered up. This reduces the power drawn to the static leakage current and the minimal clock power overhead required to enable the device to wake up from the Standby mode.

Dormant mode

The processor can be implemented in such a way as to support Dormant mode. Dormant mode is a power saving mode in which the CPU logic, but not the TCM and cache RAMs, is powered down. The CPU state, apart from the cache and TCM state, is stored to memory before entry into Dormant mode, and restored after exit. Contact ARM for more information on preparing the Cortex-R5 processor to support Dormant mode.

Shutdown mode

This mode has the entire CPU powered down. All state, including cache and TCM state, must be saved externally. After power-up, the assertion of reset returns the CPU to the run state.

For more information on the power management features, see Chapter 10 Power Control.

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