66.3.2.3 Ultra Low-power (ULP) Mode
Ultra Low-power mode achieves the lowest power consumption with the system in Retention mode and able to resume on wake-up events (any interrupt or hardware event). This mode is a combination of the Wait for Interrupt mode of the Arm core and a reduced frequency or shut-off of the system clocks.
To obtain the best results, care must be taken that the I/Os (pull-up/pull-down, etc.), USB transceivers, etc., are set to the appropriate state.
The Ultra Low-power mode features two submodes:
- ULP0 mode
- ULP1 mode