Datasheet

49
32072H–AVR32–10/2012
AT32UC3A3
The power level of the internal voltage regulator is also adjusted according to the sleep mode to
reduce the internal regulator power consumption.
7.5.7.3 Precautions when entering sleep mode
Modules communicating with external circuits should normally be disabled before entering a
sleep mode that will stop the module operation. This prevents erratic behavior when entering or
exiting sleep mode. Please refer to the relevant module documentation for recommended
actions.
Communication between the synchronous clock domains is disturbed when entering and exiting
sleep modes. This means that bus transactions are not allowed between clock domains affected
by the sleep mode. The system may hang if the bus clocks are stopped in the middle of a bus
transaction.
The CPU is automatically stopped in a safe state to ensure that all CPU bus operations are com-
plete when the sleep mode goes into effect. Thus, when entering Idle mode, no further action is
necessary.
When entering a sleep mode (except Idle mode), all HSB masters must be stopped before
entering the sleep mode. Also, if there is a chance that any PB write operations are incomplete,
the CPU should perform a read operation from any register on the PB bus before executing the
sleep instruction. This will stall the CPU while waiting for any pending PB operations to
complete.
When entering a sleep mode deeper or equal to DeepStop, the VBus asynchronous interrupt
should be disabled (USBCON.VBUSTE = 0).
7.5.7.4 Wake Up
The USB can be used to wake up the part from sleep modes through register AWEN of the
Power Manager.
7.5.8 Generic Clocks
Timers, communication modules, and other modules connected to external circuitry may require
specific clock frequencies to operate correctly. The Power Manager contains an implementation
defined number of generic clocks that can provide a wide range of accurate clock frequencies.
Table 7-1. Sleep Modes
Index Sleep Mode CPU HSB
PBA,B
GCLK
Osc0,1
PLL0,1,
SYSTIMER Osc32 RCSYS
BOD &
BOD33 &
Bandgap
Voltage
Regulator
0 Idle Stop Run Run Run Run Run On Full power
1 Frozen Stop Stop Run Run Run Run On Full power
2 Standby Stop Stop Stop Run Run Run On Full power
3 Stop Stop Stop Stop Stop Run Run On Low power
4 DeepStop Stop Stop Stop Stop Run Run Off Low power
5 Static Stop Stop Stop Stop Stop Stop Off Low power