Datasheet

20
11090BS–ATARM–22-Oct-13
SAM3S8/SD8 Summary
5.7 Fast Startup
The SAM3S8/SD8 allows the processor to restart in a few microseconds while the processor is
in wait mode or in sleep mode. A fast start up can occur upon detection of a low level on one of
the 19 wake-up inputs (WKUP0 to 15 + SM + RTC + RTT).
The fast restart circuitry, as shown in Figure 5-5, is fully asynchronous and provides a fast start-
up signal to the Power Management Controller. As soon as the fast start-up signal is asserted,
the PMC automatically restarts the embedded 4 MHz Fast RC oscillator, switches the master
clock on this 4MHz clock and reenables the processor clock.
Figure 5-5. Fast Start-Up Sources
RTCEN
rtc_alarm
RTTEN
rtt_alarm
USBEN
usb_wakeup
fast_restart
WKUP15
FSTT15
WKUP1
WKUP0
FSTT0
FSTT1
Falling/Rising
Edge
Detector
Falling/Rising
Edge
Detector
Falling/Rising
Edge
Detector