67.4.2.3 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