ATMEGA2561V ATMEL [ATMEL Corporation], ATMEGA2561V Datasheet - Page 60

• Manufacturer Part Number: ATMEGA2561V
• Description: 8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Brown-out Detection
60
ATmega640/1280/1281/2560/2561
ATmega640/1280/1281/2560/2561 has an On-chip Brown-out Detection (BOD) circuit
for monitoring the V
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 detec-
tion level should be interpreted as V
Table 27. BODLEVEL Fuse Coding
Note:
Table 28. Brown-out Characteristics
When the BOD is enabled, and V
in Figure 28), the Brown-out Reset is immediately activated. When V
the trigger level (V
out period t
The BOD circuit will only detect a drop in V
for longer than t
Figure 28. Brown-out Reset During Operation
Symbol
V
t
BOD
HYST
BODLEVEL 2:0 Fuses
1. V
TOUT
devices where this is the case, the device is tested down to V
production test. This guarantees that a Brown-Out Reset will occur before V
to a voltage where correct operation of the microcontroller is no longer guaranteed.
The test is performed using BODLEVEL = 110 for 4 MHz operation of
ATmega640V/1280V/1281V/2560V/2561V, BODLEVEL = 101 for 8 MHz operation of
ATmega640V/1280V/1281V/2560V/2561V
BODLEVEL = 100 for 16 MHz operation of ATmega640/1280/1281/2560/2561.
INTERNAL
BOT
TIME-OUT
Parameter
Brown-out Detector Hysteresis
Min Pulse Width on Brown-out Reset
111
110
101
100
011
010
001
000
RESET
RESET
BOD
has expired.
may be below nominal minimum operating voltage for some devices. For
V
CC
BOT+
CC
given in Table 26.
level during operation by comparing it to a fixed trigger level. The
in Figure 28), the delay counter starts the MCU after the Time-
CC
V
BOT-
BOT+
(1)
Min V
decreases to a value below the trigger level (V
1.7
2.5
4.1
= V
BOT
CC
BOT
if the voltage stays below the trigger level
+ V
Typ V
HYST
and
1.8
2.7
4.3
BOD Disabled
/2 and V
Reserved
BOT
V
Min
t
TOUT
BOT+
ATmega640/1280/1281,
BOT-
Typ
50
Max V
CC
2.0
2.9
4.5
= V
CC
increases above
BOT
= V
Max
BOT
2549K–AVR–01/07
BOT
- V
during the
HYST
CC
Units
Units
mV
ns
V
drops
/2.
BOT-
and