Datasheet

503
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
The fast start-up circuitry, as shown in Figure 29-4, 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 embedded 4/8/12 MHz fast RC oscillator
restarts automatically.
When entering wait mode, the embedded Flash can be placed in one of the low-power modes (deep-power-down or
standby) depending on the configuration of the FLPM field in the PMC_FSMR. The FLPM field can be programmed at
anytime and its value will be applied to the next wait mode period.
The power consumption reduction is optimal when configuring 1 (deep-power-down mode) in field FLPM. If 0 is
programmed (standby mode), the power consumption is slightly higher than in deep-power-down mode.
When programming 2 in field FLPM, the wait mode Flash power consumption is equivalent to that of the active mode
when there is no read access on the Flash.
Figure 29-4. Fast Start-up Circuitry
Each wake-up input pin and alarm can be enabled to generate a fast start-up event by setting the corresponding bit in the
Fast Start-up Mode Register (PMC_FSMR).
The user interface does not provide any status for fast start-up, but the user can easily recover this information by
reading the PIO Controller and the status registers of the RTC, RTT and USB Controller.
29.12 Start-up from Embedded Flash
The inherent start-up time of the embedded Flash cannot provide a fast start-up of the system.
If system fast start-up time is not required, the first instruction after a wait mode exit can be located in the embedded
Flash. Under these conditions, prior to entering wait mode, the Flash controller must be programmed to perform access
in 0 wait-state (see Flash controller section).
fast_restart
WKUP15
FSTT15
FSTP15
WKUP1
FSTT1
FSTP1
WKUP0
FSTT0
FSTP0
RTTAL
RTCAL
USBAL
RTT Alarm
RTC Alarm
USB Alarm