Microchip Technology MA330031-2 Data Sheet
2011-2013 Microchip Technology Inc.
DS70000657H-page 163
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X AND PIC24EPXXXGP/MC20X
10.0
POWER-SAVING FEATURES
The dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/
50X and PIC24EPXXXGP/MC20X devices provide
the ability to manage power consumption by
selectively managing clocking to the CPU and the
peripherals. In general, a lower clock frequency and
a reduction in the number of peripherals being
clocked constitutes lower consumed power.
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X
and PIC24EPXXXGP/MC20X devices can manage
power consumption in four ways:
• Clock Frequency
• Instruction-Based Sleep and Idle modes
• Software-Controlled Doze mode
• Selective Peripheral Control in Software
Combinations of these methods can be used to selec-
tively tailor an application’s power consumption while
still maintaining critical application features, such as
timing-sensitive communications.
50X and PIC24EPXXXGP/MC20X devices provide
the ability to manage power consumption by
selectively managing clocking to the CPU and the
peripherals. In general, a lower clock frequency and
a reduction in the number of peripherals being
clocked constitutes lower consumed power.
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X
and PIC24EPXXXGP/MC20X devices can manage
power consumption in four ways:
• Clock Frequency
• Instruction-Based Sleep and Idle modes
• Software-Controlled Doze mode
• Selective Peripheral Control in Software
Combinations of these methods can be used to selec-
tively tailor an application’s power consumption while
still maintaining critical application features, such as
timing-sensitive communications.
10.1
Clock Frequency and Clock
Switching
Switching
The dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/
50X and PIC24EPXXXGP/MC20X devices allow a
wide range of clock frequencies to be selected under
application control. If the system clock configuration is
not locked, users can choose low-power or high-
precision oscillators by simply changing the NOSCx
bits (OSCCON<10:8>). The process of changing a
system clock during operation, as well as limitations to
the process, are discussed in more detail in
50X and PIC24EPXXXGP/MC20X devices allow a
wide range of clock frequencies to be selected under
application control. If the system clock configuration is
not locked, users can choose low-power or high-
precision oscillators by simply changing the NOSCx
bits (OSCCON<10:8>). The process of changing a
system clock during operation, as well as limitations to
the process, are discussed in more detail in
.
10.2
Instruction-Based Power-Saving
Modes
Modes
The dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/
50X and PIC24EPXXXGP/MC20X devices have two
special power-saving modes that are entered
through the execution of a special PWRSAV
instruction. Sleep mode stops clock operation and
halts all code execution. Idle mode halts the CPU
and code execution, but allows peripheral modules
to continue operation. The assembler syntax of the
PWRSAV
50X and PIC24EPXXXGP/MC20X devices have two
special power-saving modes that are entered
through the execution of a special PWRSAV
instruction. Sleep mode stops clock operation and
halts all code execution. Idle mode halts the CPU
and code execution, but allows peripheral modules
to continue operation. The assembler syntax of the
PWRSAV
instruction is shown in
Sleep and Idle modes can be exited as a result of an
enabled interrupt, WDT time-out or a device Reset. When
the device exits these modes, it is said to “wake-up”.
enabled interrupt, WDT time-out or a device Reset. When
the device exits these modes, it is said to “wake-up”.
EXAMPLE 10-1:
PWRSAV
INSTRUCTION SYNTAX
Note 1:
This data sheet summarizes the
features of the dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X and
PIC24EPXXXGP/MC20X families of
devices. It is not intended to be a compre-
hensive reference source. To complement
the information in this data sheet, refer to
“Watchdog Timer and Power-Saving
Modes”
features of the dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X and
PIC24EPXXXGP/MC20X families of
devices. It is not intended to be a compre-
hensive reference source. To complement
the information in this data sheet, refer to
“Watchdog Timer and Power-Saving
Modes”
(DS70615) in the “dsPIC33/
PIC24 Family Reference Manual
”, which
www.microchip.com
).
2:
Some registers and associated bits
described in this section may not be
available on all devices. Refer to
described in this section may not be
available on all devices. Refer to
in
this data sheet for device-specific register
and bit information.
and bit information.
Note:
SLEEP_MODE
and IDLE_MODE are con-
stants defined in the assembler include
file for the selected device.
file for the selected device.
PWRSAV
#SLEEP_MODE
; Put the device into Sleep mode
PWRSAV
#IDLE_MODE
; Put the device into Idle mode