Datasheet

6500CS–ATARM–24-Jan-11

SAM3S Summary

5.7 Fast Startup

The device 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 4/8/12 MHz fast RC oscillator, switches the mas-

ter clock on this 4MHz clock and reenables the processor clock.

Figure 5-5. Fast Start-Up Circuitry

fast_restart

WKUP15

FSTT15

FSTP15

WKUP1

FSTT1

FSTP1

WKUP0

FSTT0

FSTP0

RTTAL

RTCAL

USBAL

RTT Alarm

RTC Alarm

USB Alarm