Datasheet

ATmega32A
 2018 Microchip Technology Inc. Data Sheet Complete DS40002072A-page 43
10.9 Register Description
10.9.1 MCUCR – MCU Control Register
The MCU Control Register contains control bits for power management.
• Bit 7 – 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 programmers 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.
• Bits 6:4 – SM2:0: Sleep Mode Select Bits 2, 1, and 0
These bits select between the six available sleep modes as shown in Table 10-2.
Note: 1. Standby mode and Extended Standby mode are only available with external crystals or resonators.
Bit 76543210
SE SM2 SM1 SM0
ISC11 ISC10 ISC01 ISC00 MCUCR
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 10-2. Sleep Mode Select
SM2 SM1 SM0 Sleep Mode
000Idle
0 0 1 ADC Noise Reduction
0 1 0 Power-down
0 1 1 Power-save
100Reserved
101Reserved
1 1 0 Standby
(1)
1 1 1 Extended Standby
(1)