at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 52

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

8.1.5
52
AT90PWM81
Brown-out Detection
AT90PWM81 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
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 hys-
teresis on the detection level should be interpreted as V
V
Table 8-2.
Notes:
Table 8-3.
Notes:
When V
immediately activated. When V
ter starts the MCU after the Time-out period t
The BOD circuit will only detect a drop in V
t
BOD
Symbol
V
t
HYST
BOD
HYST
given in
/2.
BODLEVEL 2..0 Fuses
CC
1. V
2. Values are guidelines only.
1. Values are guidelines only.
( default configuration)
decreases to a value below the trigger level (V
case, the device is tested down to V
Out Reset will occur before V
longer guaranteed. The test is performed using BODLEVEL = 010 for Low Operating Voltageand
BODLEVEL = 101for High Operating Voltage.
Table
BOT
BODLEVEL Fuse Coding
Brown-out Characteristics
Parameter
Brown-out Detector Hysteresis
Min Pulse Width on Brown-out Reset
may be below nominal minimum operating voltage for some devices. For devices where this is the
111
110
101
100
011
010
001
000
8-3.
CC
increases above the trigger level (V
CC
drops to a voltage where correct operation of the microcontroller is no
(1)
(1)(2)
Min V
CC
CC
TOUT
= V
if the voltage stays below the trigger level for longer than
BOT
BOT
has expired.
during the production test. This guarantees that a Brown-
Forbidden, BOD must be enabled
BOT+
BOT-
Typ V
Min.
= V
4.5
2.7
4.3
4.4
4.2
2.8
2.6
in
BOT
Figure
BOT
BOT+
+ V
Typ.
in
70
8-5), the Brown-out Reset is
2
HYST
Figure
Max V
/2 and V
8-5), the delay coun-
BOT
Max.
CC
7734M–AVR–03/10
BOT-
level during
= V
Units
Units
mV
V
V
V
V
V
V
V
µs
BOT
-