Rainbow Electronics ATmega64M1 - Manual (Page 46)

46
8209A–AVR–08/09
ATmega16M1/32M1/64M1
Figure 11-5. Brown-out Reset During Operation
11.2.4 Watchdog Reset
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
TOUT
. Refer to
page 47 for details on operation of the Watchdog Timer.
Figure 11-6. Watchdog Reset During Operation
11.3 Internal Voltage Reference
ATmega16M1/32M1/64M1 features an internal bandgap reference. This reference is used for
Brown-out DetectionDetection, and it can be used as an input to the Analog Comparators or the
ADC. The V
REF
2.56V reference to the ADC, DAC or Analog Comparators is generated from the
internal bandgap reference.
11.3.1 Voltage Reference Enable Signals and Start-up Time
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in
“System and Reset Characteristics” on page 313 . To save power, the
reference is not always turned on. The reference is on during the following situations:
V
CC
RESET
TIME-OUT
INTERNAL
RESET
V
BOT-
V
BOT+
t
TOUT
CK
CC