SAM3N00A Atmel Corporation, SAM3N00A Datasheet - Page 345

• Manufacturer Part Number: SAM3N00A
• Manufacturer: Atmel Corporation

24.10 Fast Startup
11011A–ATARM–04-Oct-10
The SAM3N device allows the processor to restart in less than10 µs while the device is in Wait
mode. The system enters Wait mode either by writing the WAITMODE bit at 1 in the PMC Clock
Generator Main Oscillator Register (CKGR_MOR), or by executing the WaitForEvent (WFE)
instruction of the processor while the LPM bit is at 1 in the PMC Fast Startup Mode Register
(PMC_FSMR).
A Fast Startup is enabled upon the detection of a programmed level on one of the 16 wake-up
inputs (WKUP) or upon an active alarm from the RTC and RTT. The polarity of the 16 wake-up
inputs is programmable by writing the PMC Fast Startup Polarity Register (SUPC_FSPR).
The Fast Restart circuitry, as shown in
startup signal to the Power Management Controller. As soon as the fast startup signal is
asserted, this automatically restarts the embedded 4/8/12 MHz Fast RC oscillator.
Figure 24-3. Fast Startup Circuitry
Each wake-up input pin and alarm can be enabled to generate a Fast Startup event by writing at
1 the corresponding bit in the Fast Startup Mode Register SUPC_FSMR.
The user interface does not provide any status for Fast Startup, but the user can easily recover
this information by reading the PIO Controller, and the status registers of the RTC and RTT.
WKUP15
WKUP0
WKUP1
RTT Alarm
RTC Alarm
FSTP0
FSTP1
FSTP15
FSTT0
FSTT1
FSTT15
RTTAL
RTCAL
Figure
24-3, is fully asynchronous and provides a fast
fast_restart
SAM3N
345