4.3 Power Management - ULP1

SAM9X60 introduces Ultra-Low Power 1 (ULP1) mode. In this mode, all clocks in the system are fed with the main clock (internal fast 12 MHz RC oscillator) and the main crystal is disabled. Power consumption is lower than ULP0 and wake-up time is far shorter (a few µs vs. a few ms in ULP0). The system wakes up with a programmable event (RTC/RTT alarm, USB Resume, Wake-On-LAN, WKUP1..13 lines).

One major use case for ULP1 is the support of USB device Suspend mode. In such applications, the MPU is powered by the USV VBUS rail. The total power allocated to a USB power system is 12.5 mW at 5V.

If USB Host applications are used, the suspend control of the USB PHYs must be implemented in the Special Function Registers (SFR), as they are not managed by the EHCI/OHCI peripherals.

ULP1 is controlled with bit PMC_MOR.ULP1.