ATAM894X-TNQY ATMEL [ATMEL Corporation], ATAM894X-TNQY Datasheet - Page 21

• Manufacturer Part Number: ATAM894X-TNQY
• Description: 8k-flash Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

5.6
4679D–4BMCU–05/05
Power-down Modes
Table 5-7.
Note:
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:
The ATAM894 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 programmable
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 oscil-
lator is stopped or the 32-kHz oscillator is selected, power consumption is extremely low.
Table 5-8.
I
Note:
total
Power-down
Mode
SLEEP
Active
Mode
1
2
3
4
V
DD
If the bit CCS = 0 in the CM-register the RC-oscillator 1 always stops.
1. Osc-Stop = SLEEP and NSTOP and WDL
,f
syscl
OS1
1
0
1
0
Oscillator Select
Power-down Modes
CPU Core
=
SLEEP
SLEEP
RUN
I
Sleep
OS0
1
1
0
0
+
I
DD
Stop
Osc-
YES
NO
NO
Input for SUBCL
t
------------- -
active
t
(1)
total
32 kHz
C
C
C
in
in
in
Brown-out
I
/16
/16
/16
Function
DD
Active
Active
STOP
depends on V
Selected Oscillators
RC-oscillator 1 and external input clock
RC-oscillator 1 and RC-oscillator 2
RC-oscillator 1 and 4-MHz crystal oscillator
RC-oscillator 1 and 32-kHz crystal oscillator
4-MHz Oscillator
RC-Oscillator 1
RC-Oscillator 2
DD
STOP
RUN
RUN
and f
syscl
Oscillator
32-kHz
RUN
RUN
RUN
ATAM894
Input Clock
External
STOP
YES
YES
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