3.6. Wakeup Interrupt Controller (WIC)

The Wakeup Interrupt Controller (WIC) is a peripheral that can detect an interrupt and wake the processor from deep sleep mode. The WIC is enabled only when the system is in deep sleep mode.

The WIC is not programmable, and does not have any registers or user interface. It operates entirely from hardware signals.

When the WIC is enabled and the processor enters deep sleep mode, the power management unit in the system can power down most of the Cortex-M3 processor. When the WIC receives an interrupt, it takes a number of clock cycles to wakeup the processor and restore its state to enable it to process the interrupt. This means interrupt latency is increased in deep sleep mode.


Unlike in the standard Cortex-M3, the IoT System WIC is implemented by latches. This means that FCLK can be gated completely during WIC based deep sleep. This is not a standard CM3 feature.

For more information on the WIC, see the Cortex-M3 Technical Reference Manual.

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