If the PB input is pulled low for 8 s (15 s if TRST = 1b) or longer, then all rails except for DCDC5 and DCDC6 are disabled, and the device enters the RECOVERY state. The device powers up automatically after the 500 ms power-down sequence is complete, regardless of the state of the PB input. Holding the PB pin low for 8 s (15 s if TRST = 1b), only turns off the device temporarily and forces a system restart, and is not a power-down function. If the PB is held low continuously, the device power-cycles in 8-s and 15-s intervals.