Datasheet

• Brown-out Reset

• 2-wire Serial Interface address match

• Timer/Counter interrupt

• SPM/EEPROM ready interrupt

• External level interrupt on INT

• Pin change interrupt

Note: 1. Timer/Counter will only keep running in asynchronous mode.

Related Links

8-bit Timer/Counter2 with PWM and Asynchronous Operation on page 188

11.6. Power-Down Mode

When the SM[2:0] bits are written to '010', the SLEEP instruction makes the MCU enter Power-Down

mode. In this mode, the external Oscillator is stopped, while the external interrupts, the 2-wire Serial

Interface address watch, and the Watchdog continue operating (if enabled).

Only one of these events can wake up the MCU:

• External Reset

• Watchdog System Reset

• Watchdog Interrupt

• Brown-out Reset

• 2-wire Serial Interface address match

• External level interrupt on INT

• Pin change interrupt

This sleep mode basically halts all generated clocks, allowing operation of asynchronous modules only.

Note: If a level triggered interrupt is used for wake-up from Power-Down, the required level must be held

long enough for the MCU to complete the wake-up to trigger the level interrupt. If the level disappears

before the end of the Start-up Time, the MCU will still wake up, but no interrupt will be generated. The

start-up time is defined by the SUT and CKSEL Fuses.

When waking up from Power-Down mode, there is a delay from the wake-up condition occurs until the

wake-up becomes effective. This allows the clock to restart and become stable after having been

stopped. The wake-up period is defined by the same CKSEL Fuses that define the Reset Time-out

period.