Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD 数据表
产品代码
ATSAM4S-WPIR-RD
29
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
preserved when in backup mode, any free PIO line can be used to switch off the external regulator by driving the
PIO line at low level (PIO is input, pull-up enabled after backup reset). External wake-up of the system can be from
for further details.
Figure 5-3.
Backup Battery
5.4
Active Mode
Active mode is the normal running mode with the core clock running from the fast RC oscillator, the main crystal
oscillator or the PLLA. The Power Management Controller can be used to adapt the frequency and to disable the
peripheral clocks.
5.5
Low-power Modes
The SAM4S has the following low-power modes: backup mode, wait mode and sleep mode.
Note:
The Wait For Event instruction (WFE) of the Cortex-M4 core can be used to enter any of the low-power modes, how-
ever, this may add complexity in the design of application state machines. This is due to the fact that the WFE
instruction goes along with an event flag of the Cortex core (cannot be managed by the software application). The
event flag can be set by interrupts, a debug event or an event signal from another processor. Since it is possible for an
interrupt to occur just before the execution of WFE, WFE takes into account events that happened in the past. As a
result, WFE prevents the device from entering wait mode if an interrupt event has occurred.
Atmel has made provision to avoid using the WFE instruction. The workarounds to ease application design are as fol-
lows:
- For backup mode, switch off the voltage regulator and configure the VROFF bit in the Supply Controller Control Reg-
ister (SUPC_CR).
- For wait mode, configure the WAITMODE bit in the PMC Clock Generator Main Oscillator Register of the Power Man-
agement Controller (PMC)
- For sleep mode, use the Wait for Interrupt (WFI) instruction.
ever, this may add complexity in the design of application state machines. This is due to the fact that the WFE
instruction goes along with an event flag of the Cortex core (cannot be managed by the software application). The
event flag can be set by interrupts, a debug event or an event signal from another processor. Since it is possible for an
interrupt to occur just before the execution of WFE, WFE takes into account events that happened in the past. As a
result, WFE prevents the device from entering wait mode if an interrupt event has occurred.
Atmel has made provision to avoid using the WFE instruction. The workarounds to ease application design are as fol-
lows:
- For backup mode, switch off the voltage regulator and configure the VROFF bit in the Supply Controller Control Reg-
ister (SUPC_CR).
- For wait mode, configure the WAITMODE bit in the PMC Clock Generator Main Oscillator Register of the Power Man-
agement Controller (PMC)
- For sleep mode, use the Wait for Interrupt (WFI) instruction.
Complete information is available in
.
ADC, DAC
Analog Comp.
USB
Transceivers.
VDDIN
Voltage
Regulator
3.3V
LDO
LDO
Backup
Battery
Battery
+
-
ON/OFF
IN
OUT
VDDOUT
Main Supply
VDDCORE
ADC, DAC, Analog
Comparator Supply
(2.4V-3.6V)
Comparator Supply
(2.4V-3.6V)
VDDIO
VDDPLL
PIOx (Output)
WAKEUPx
External wakeup signal
Note: The two diodes provide a “switchover circuit” (for illustration purpose)
between the backup battery and the main supply when the system is put in
backup mode.
between the backup battery and the main supply when the system is put in
backup mode.