ATmega640/1280/1281/2560/2561
31.5 System and Reset Characteristics
Table 31-3. Reset, Brown-out and Internal voltage CharacteristicsCharacteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
Power-on Reset Threshold Voltage
(rising)
0.7
1.0
1.4
V
VPOT
Power-on Reset Threshold Voltage
(falling)(1)
0.05
0.9
1.3
V
VPSR
VRST
tRST
VHYST
tBOD
VBG
tBG
Power-on slope rate
0.01
4.5
0.9VCC
2.5
V/ms
V
RESET Pin Threshold Voltage
Minimum pulse width on RESET Pin
Brown-out Detector Hysteresis
Min Pulse Width on Brown-out Reset
Bandgap reference voltage
0.2VCC
ns
50
2
mV
ns
VCC=2.7V,TA= 25°C
VCC=2.7V,TA= 25°C
VCC=2.7V,TA= 25°C
1.0
1.1
40
10
1.2
70
V
Bandgap reference start-up time
Bandgap reference current consumption
µs
IBG
µA
Note:
1. The Power-on Reset will not work unless the supply voltage has been below VPOT (falling).
Table 31-4. BODLEVEL Fuse Coding(1)
BODLEVEL 2:0 Fuses
Min VBOT
Typ VBOT
Max VBOT
Units
111
110
101
100
011
010
001
000
BOD Disabled
1.7
2.5
4.1
1.8
2.7
4.3
2.0
2.9
4.5
V
Reserved
Note:
1. VBOT may be below nominal minimum operating voltage for some devices. For devices where this is the case, the device is
tested down to VCC = VBOT during the production test. This guarantees that a Brown-Out Reset will occur before VCC drops 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 and ATmega640/1280/1281, and BODLEVEL = 100 for 16 MHz operation of
ATmega640/1280/1281/2560/2561
31.6 2-wire Serial Interface Characteristics
Table 31-5 describes the requirements for devices connected to the 2-wire Serial Bus. The
ATmega640/1280/1281/2560/2561 2-wire Serial Interface meets or exceeds these requirements under the noted
conditions.
375
2549L–AVR–08/07
ATMEL [ ATMEL ]
