PIC24FJ64GA datasheet(97/262 Pages) MICROCHIP

97 / 262 page

Preliminary

DS39881C-page 95

PIC24FJ64GA004 FAMILY

8.0

POWER-SAVING FEATURES

The PIC24FJ64GA004 family of devices provides 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 circuits being clocked constitutes lower

consumed power. All PIC24F devices manage power

consumption in four different 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.

8.1

Clock Frequency and Clock

Switching

PIC24F devices allow for 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 NOSC bits. The process of changing a sys-

tem clock during operation, as well as limitations to the

process, are discussed in more detail in Section 7.0

“Oscillator Configuration”.

8.2

Instruction-Based Power-Saving

Modes

PIC24F 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 assembly syntax of the

PWRSAV instruction is shown in Example 8-1.

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”.

8.2.1

SLEEP MODE

Sleep mode has these features:

• The system clock source is shut down. If an

on-chip oscillator is used, it is turned off.

• The device current consumption will be reduced

to a minimum provided that no I/O pin is sourcing

current.

• The Fail-Safe Clock Monitor does not operate

during Sleep mode since the system clock source

is disabled.

• The LPRC clock will continue to run in Sleep

mode if the WDT is enabled.

• The WDT, if enabled, is automatically cleared

prior to entering Sleep mode.

• Some device features or peripherals may

continue to operate in Sleep mode. This includes

items such as the input change notification on the

I/O ports, or peripherals that use an external clock

input. Any peripheral that requires the system

clock source for its operation will be disabled in

Sleep mode.

The device will wake-up from Sleep mode on any of the

these events:

• On any interrupt source that is individually

enabled

• On any form of device Reset

• On a WDT time-out

On wake-up from Sleep, the processor will restart with

the same clock source that was active when Sleep

mode was entered.

EXAMPLE 8-1:

PWRSAV INSTRUCTION SYNTAX

Note:

This data sheet summarizes the features

of this group of PIC24F devices. It is not

intended to be a comprehensive reference

source. For more information, refer to the

“PIC24F Family Reference Manual”,

”Section 10. Power-Saving Features”

(DS39698). Additional power-saving tips

can also be found in Appendix B: “Addi-

tional Guidance for PIC24FJ64GA004

Family Applications” of this document.

Note:

SLEEP_MODE and IDLE_MODE are con-

stants defined in the assembler include

file for the selected device.

PWRSAV

#SLEEP_MODE

; Put the device into SLEEP mode

PWRSAV

#IDLE_MODE

; Put the device into IDLE mode

PIC24FJ64GA датащи(PDF) 97 Page - Microchip Technology

PIC24FJ64GA датащи(HTML) 97 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL