Atmel SAM4L Xplained Pro Evaluation Kit Atmel ATSAM4L-XPRO ATSAM4L-XPRO Data Sheet

42023E–SAM–07/2013

The following table shows a summary of the main Power Save modes:

The Power Scaling technique consists of adjusting the internal regulator output voltage (voltage
scaling) to reduce the power consumption. According to the requirements in terms of perfor-
mance, operating modes, and current consumption, the user can select the Power Scaling
configuration that fits the best with its application.

The Power Scaling configuration field (PMCON.PS) is provided in the Backup Power Manager
(BPM) module.

In RUN mode, the user can adjust on the fly the Power Scaling configuration

The 

 summarizes the different combination of the Power Scaling configuration which

can be applied according to the Power Save Mode.

Power scaling from a current power configuration to a new power configuration is done by halt-
ing the CPU execution

Power scaling occurs after a WFI instruction. The system is halted until the new power configu-
ration is stabilized. After handling the PM interrupt, the system resumes from WFI.

To scale the power, the following sequence is required:

• Check the BPM.SR.PSOK bit to make sure the current power configuration is stabilized.

Power Save mode Configuration Summary

SLEEP

WFI

SCR.SLEEPDEEP bit = 0 

BPM.PMCON.BKUP bit = 0

Any interrupt

CPU clock OFF

Other clocks OFF depending 
on the BPM.PMCON.SLEEP 
field

Clocks OFF depending on 
the BPM.PMCON.SLEEP 
field

see 

WAIT

WFI

SCR.SLEEPDEEP bit = 1

BPM.PMCON.RET bit = 0

BPM.PMCON.BKUP bit = 0

PM WAKE interrupt

All clocks are OFF

Core domain is retained

All clocks are OFF except 
RC32K or OSC32K if 
running

RETENTION

WFI

SCR.SLEEPDEEP bit = 1 

BPM.PMCON.RET bit = 1

BPM.PMCON.BKUP bit = 0

PM WAKE interrupt

All clocks are OFF

Core domain is retained

All clocks are OFF except 
RC32K or OSC32K if 
running

BACKUP

WFI

+ SCR.SLEEPDEEP bit = 1 

+ BPM.PMCON.BKUP bit = 1

EIC interrupt

BOD33, BOD18 interrupt 
and reset

AST alarm, periodic, 
overflow

WDT interrupt and reset

external reset on RESET_N 
pin

OFF (not powered)

All clocks are OFF except 
RC32K or OSC32K if 
running