ATMEGA128-16AU SL383 Atmel, ATMEGA128-16AU SL383 Datasheet - Page 53

• Manufacturer Part Number: ATMEGA128-16AU SL383
• Manufacturer: Atmel

Brown-out Detection
2467S–AVR–07/09
Figure 25. External Reset During Operation
ATmega128 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
ing operation by comparing it to a fixed trigger level. The trigger level for the BOD can be
selected by the fuse BODLEVEL to be 2.7V (BODLEVEL unprogrammed), or 4.0V (BODLEVEL
programmed). 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
The BOD circuit can be enabled/disabled by the fuse BODEN. When the BOD is enabled
(BODEN programmed), and V
26), the Brown-out Reset is immediately activated. When V
(V
expired.
The BOD circuit will only detect a drop in V
ger than t
Figure 26. Brown-out Reset During Operation
BOT
BOT+
- V
in
HYST
BOD
Figure
/2.
given in
CC
INTERNAL
TIME-OUT
26), the delay counter starts the MCU after the time-out period t
RESET
RESET
V
Table
CC
19.
CC
decreases to a value below the trigger level (V
V
BOT-
CC
if the voltage stays below the trigger level for lon-
CC
V
BOT+
t
TOUT
BOT+
increases above the trigger level
= V
BOT
ATmega128
+ V
HYST
/2 and V
BOT-
CC
level dur-
TOUT
in
Figure
BOT-
has
53
=