When the BOD is enabled, and VCC decreases to a value below the trigger level (VBOT- in Figure 7-5 on page 41), the brown-
out reset is immediately activated. When VCC increases above the trigger level (VBOT+ in Figure 7-5 on page 41), the delay
counter starts the MCU after the Time-out period tTOUT has expired.
The BOD circuit will only detect a drop in VCC if the voltage stays below the trigger level for longer than tBOD given in
Table 7-3.
Figure 7-5. Brown-out Reset during Operation
VCC
VBOT+
VBOT-
RESET
tTOUT
TIME-OUT
INTERNAL
RESET
7.2.4 Watchdog Reset
When the watchdog times out, it will generate a short reset pulse of one CK cycle duration. On the falling edge of this pulse,
the delay timer starts counting the time-out period tTOUT. Refer to Section 7.4 “Watchdog Timer” on page 43 for details on
operation of the watchdog timer.
Figure 7-6. Watchdog Reset during Operation
VCC
RESET
1 CK Cycle
WDT
TIME-OUT
tTOUT
RESET
Time-OUT
INTERNAL
RESET
ATmega16/32/64/M1/C1 [DATASHEET]
41
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
