Datasheet

39
ATmega48PA/88PA/168PA [DATASHEET]
9223F–AVR–04/14
• 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.
10.11.2 MCUCR – MCU Control Register
• Bit 6 – BODS: BOD Sleep
()
The BODS bit must be written to logic one in order to turn off BOD during sleep, see Table 10-1 on page 35. Writing to the
BODS bit is controlled by a timed sequence and an enable bit, 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.
The BODS bit is active three clock cycles after it is set. A sleep instruction must be executed while BODS is active in order to
turn off the BOD for the actual sleep mode. The BODS bit is automatically cleared after three clock cycles.
• Bit 5 – BODSE: BOD Sleep Enable
()
BODSE enables setting of BODS control bit, as explained in BODS bit description. BOD disable is controlled by a timed
sequence.
Note: 1. BODS and BODSE only available for picoPower devices ATmega48PA/88PA/168PA
Table 10-2. Sleep Mode Select
SM2 SM1 SM0 Sleep Mode
0 0 0 Idle
0 0 1 ADC Noise Reduction
0 1 0 Power-down
0 1 1 Power-save
1 0 0 Reserved
1 0 1 Reserved
1 1 0 Standby
(1)
1 1 1 External Standby
(1)
Note: 1. Standby mode is only recommended for use with external crystals or resonators.
Bit 7 6 5 4 3 2 1 0
0x35 (0x55) – BODS
()
BODSE
()
PUD – – IVSEL IVCE MCUCR
Read/Write R R/W R/W R/W R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0