39
7598H–AVR–07/09
ATtiny25/45/85
When the BOD is enabled, and V
CC
decreases to a value below the trigger level (V
BOT-
in
), the Brown-out Reset is immediately activated. When V
CC
increases above the trigger level
(V
BOT+
in
), the delay counter starts the MCU after the Time-out period t
TOUT
has
expired.
The BOD circuit will only detect a drop in V
CC
if the voltage stays below the trigger level for lon-
ger than t
BOD
given in
.
Figure 8-5.
Brown-out Reset During Operation
8.6
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 t
TOUT
. Refer to
for details on operation of the Watchdog Timer.
Figure 8-6.
Watchdog Reset During Operation
V
CC
RESET
TIME-OUT
INTERNAL
RESET
V
BOT-
V
BOT+
t
TOUT
CK
CC
