ATmega325PA Atmel Corporation, ATmega325PA Datasheet - Page 44

• Manufacturer Part Number: ATmega325PA
• Manufacturer: Atmel Corporation

10.11 Register Description
10.11.1
10.11.2
8285D–AVR–06/11
SMCR – Sleep Mode Control Register
MCUCR – MCU Control Register
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
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 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.
Note:
• Bit 6 – BODS: BOD Sleep
The BODS bit must be written to logic one in order to turn off BOD during sleep, see
on page
BODSE in MCUCR. To disable BOD in relevant sleep modes, both BODS and BODSE must first
be set to one. Then, to set the BODS bit, BODS must be set to one and BODSE must be set to
zero within four clock cycles.
Bit
0x33 (0x53)
Read/Write
Initial Value
Bit
0x35 (0x55)
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.
1. Only available in the picoPower devices ATmega165PA/325PA/3250PA/645P/6450P.
39. Writing to the BODS bit is controlled by a timed sequence and an enable bit,
Sleep Mode Select
JTD
R/W
7
0
R
7
–
0
SM1
0
0
1
1
0
0
1
1
BODS
R/W
6
0
R
6
–
0
(1)
BODSE
R/W
R
5
0
5
–
0
SM0
0
1
0
1
0
1
0
1
(1)
PUD
R
R/W
4
–
0
0
4
Sleep Mode
Idle
ADC Noise Reduction
Power-down
Power-save
Reserved
Reserved
Standby
Reserved
SM2
R/W
3
0
(1)
R
3
–
0
SM1
R/W
2
0
R
2
–
0
SM0
Table
R/W
IVSEL
1
0
R/W
1
0
10-2.
R/W
SE
IVCE
R/W
0
0
0
0
Table 10-1
MCUCR
SMCR
44