Datasheet

Table Of Contents
54
ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]
2549Q–AVR–02/2014
11.10 Register Description
11.10.1 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 11-2.
Note: 1. Standby modes are only recommended for use with external crystals or resonators.
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 exe-
cuted. 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 76543210
0x33 (0x53) ––––SM2SM1SM0SESMCR
Read/WriteRRRRR/W R/W R/W R/W
Initial Value00000000
Table 11-2. Sleep Mode Select
SM2 SM1 SM0 Sleep Mode
000 Idle
001 ADC Noise Reduction
010 Power-down
011 Power-save
100 Reserved
101 Reserved
1 1 0 Standby
(1)
1 1 1 Extended Standby
(1)