ATAM893-D datasheet(21/98 Pages) ATMEL

21 / 98 page

4680C–4BMCU–01/05

ATAM893-D

Note:

If the bit CCS = 0 in the CM-register the RC-oscillator 1 always stops

4.6

Power-down Modes

The sleep mode is a shut-down condition which is used to reduce the average system power

consumption in applications where the microcontroller is not fully utilized. In this mode, the sys-

tem clock is stopped. The sleep mode is entered via the SLEEP instruction. This instruction sets

the interrupt enable bit (I) in the condition code register to enable all interrupts and stops the

core. During the sleep mode the peripheral modules remain active and are able to generate

interrupts. The microcontroller exits the sleep mode by carrying out any interrupt or a reset.

The sleep mode can only be kept when none of the interrupt pending or active register bits are

set. The application of the $AUTOSLEEP routine ensures the correct function of the sleep

mode. For standard applications use the $AUTOSLEEP routine to enter the power-down mode.

Using the SLEEP instruction instead of the $AUTOSLEEP following an I/O instruction requires

the insertion of 3 non I/O instruction cycles (for example NOP NOP NOP) between the IN or

OUT command and the SLEEP command.

The total power consumption is directly proportional to the active time of the microcontroller. For

a rough estimation of the expected average system current consumption, the following formula

should be used:

DD depends on VDD and fsyscl

The ATAM893-D has various power-down modes. During the sleep mode the clock for the

MARC4 core is stopped. With the NSTOP bit in the clock management register (CM) it is pro-

grammable if the clock for the on-chip peripherals is active or stopped during the sleep mode. If

the clock for the core and the peripherals is stopped the selected oscillator is switched off. An

exception is the 32-kHz oscillator, if it is selected it runs continuously independent of the NSTOP

bit. If the oscillator is stopped or the 32-kHz oscillator is selected, power consumption is

extremely low.

Table 4-7.

Oscillator Select

Mode

OS1

OS0

Input for SUBCL

Selected Oscillators

in/16

RC-oscillator 1 and external input clock

in/16

RC-oscillator 1 and RC-oscillator 2

in/16

RC-oscillator 1 and 4-MHz crystal oscillator

32 kHz

RC-oscillator 1 and 32-kHz crystal oscillator

Table 4-8.

Power-down Modes

Mode

CPU Core

Osc-

Stop

(1)

Brown-out

Function

RC-Oscillator 1

RC-Oscillator 2

4-MHz Oscillator

32-kHz

Oscillator

External

Input Clock

Active

RUN

Active

RUN

YES

Power-down

SLEEP

Active

RUN

YES

SLEEP

YES

STOP

RUN

STOP

Note:

Osc-Stop = SLEEP and NSTOP and WDL

total VDD,fsyscl

()

Sleep

active

total

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ATAM893-D Datasheet(PDF) 21 Page - ATMEL Corporation

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