atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 38

• Manufacturer Part Number: atmega3250v-8auatmega325v-8ai
• Description: Atmega3250 8-bit Microcontroller With In-system Programmable Flash
• Manufacturer: ATMEL Corporation

10.9
10.9.1
38
Register Description
ATmega325/3250/645/6450
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 10-2.
Note:
• Bit 1 – 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 mode is only recommended for use with external crystals or resonators.
Sleep Mode Select
R
7
–
0
SM1
0
0
1
1
0
0
1
1
R
6
–
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
Reserved
SM2
R/W
3
0
(1)
SM1
R/W
2
0
SM0
R/W
1
0
Table
R/W
SE
0
0
10-2.
SMCR
2570L–AVR–08/07