Datasheet

23
11011B–ATARM–21-Feb-12
SAM3N
5.7 Fast Start-Up
The SAM3N allows the processor to restart in a few microseconds while the processor is in wait
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 4 MHz clock and reenables the processor clock.
Figure 5-5. Fast Start-Up Sources
RTCEN
rtc_alarm
RTTEN
rtt_alarm
fast_restart
WKUP15
FSTT15
WKUP0
FSTT0
High/Low
Level
Detector
High/Low
Level
Detector