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11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
5.7
Fast Startup
The SAM4S 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
, 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 4/8/12 MHz Fast RC oscillator, switches the mas-
ter clock on this 4 MHz clock and reenables the processor clock.
Figure 5-5.
Fast Start-Up Sources
fast_restart
WKUP15
FSTT15
FSTP15
WKUP1
FSTT1
FSTP1
WKUP0
FSTT0
FSTP0
RTTAL
RTCAL
USBAL
RTT Alarm
RTC Alarm
USB Alarm
Summary of Contents for SAM4S Series
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