ATMEGA644PV ATMEL [ATMEL Corporation], ATMEGA644PV Datasheet - Page 47

• Manufacturer Part Number: ATMEGA644PV
• Description: 8-bit Microcontroller with 16/32/64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

8.12
8.12.1
8011D–AVR–02/07
Register Description
SMCR – Sleep Mode Control Register
The Sleep Mode Control Register contains control bits for power management.
• Bits 3, 2, 1 – SM2:0: Sleep Mode Select Bits 2, 1, and 0
These bits select between the five available sleep modes as shown in
Table 8-2.
Note:
• Bit 0 – SE: Sleep Enable
The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP
instruction is executed. To avoid the MCU entering the sleep mode unless it is the programmer’s
purpose, it is recommended to write the Sleep Enable (SE) bit to one just before the execution of
the SLEEP instruction and to clear it immediately after waking up.
Bit
0x33 (0x53)
Read/Write
Initial Value
SM2
0
0
0
0
1
1
1
1
1. Standby modes are only recommended for use with external crystals or resonators.
Sleep Mode Select
7
–
R
0
SM1
0
0
1
1
0
0
1
1
6
–
R
0
R
5
–
0
SM0
0
1
0
1
0
1
0
1
R
4
–
0
Sleep Mode
Idle
ADC Noise Reduction
Power-down
Power-save
Reserved
Reserved
Standby
Extended Standby
ATmega164P/324P/644P
SM2
R/W
3
0
(1)
SM1
R/W
2
0
(1)
SM0
R/W
Table
1
0
8-2.
R/W
SE
0
0
SMCR
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