ATA8741 ATMEL Corporation, ATA8741 Datasheet - Page 59

• Manufacturer Part Number: ATA8741
• Manufacturer: ATMEL Corporation

16.0.5
16.0.6
9140B–INDCO–07/09
Brown-out Detection
Watchdog Reset
ATtiny24/44/84 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
during operation by comparing it to a fixed trigger level. The trigger level for the BOD can be
selected by the BODLEVEL Fuses. The trigger level has a hysteresis to ensure spike free
Brown-out Detection. The hysteresis on the detection level should be interpreted as V
V
When the BOD is enabled, and V
16-5 on page
trigger level (V
Time-out period t
The BOD circuit will only detect a drop in V
ger than t
Figure 16-5. Brown-out Reset During Operation
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
“Watchdog Timer” on page 60
Figure 16-6. Watchdog Reset During Operation
BOT
+ V
HYST
BOD
CC
/2 and V
given in
59), the Brown-out Reset is immediately activated. When V
INTERNAL
TIME-OUT
BOT+
TOUT
RESET
RESET
V
in
CC
BOT-
has expired.
“System and Reset Characterizations” on page
Figure 16-5 on page
= V
BOT
for details on operation of the Watchdog Timer.
- V
CC
HYST
decreases to a value below the trigger level (V
V
CK
BOT-
/2.
CC
59), the delay counter starts the MCU after the
if the voltage stays below the trigger level for lon-
V
t
TOUT
BOT+
198.
CC
increases above the
ATA8741
BOT-
TOUT
in
CC
BOT+
Figure
. See
level
59
=