at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 55

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

8.3.2
8.4
7734M–AVR–03/10
Watchdog Timer
Voltage Reference Characteristics
Thus, when the BOD is not enabled, after enabling the ADC, comparator or the internal reference, the user
must always allow the reference to start up before the output from the Analog Comparator or ADC or
DAC is used. To reduce power consumption in Power-down mode, the user can avoid the four conditions
above to ensure that the reference is turned off before entering Power-down mode.
Table 8-4.
Note:
AT90PWM81 has an Enhanced Watchdog Timer (WDT). The main features are:
•
•
•
•
Figure 8-7.
The Watchdog Timer (WDT) is a timer counting cycles of a separate on-chip 128 kHz oscillator. The
WDT gives an interrupt or a system reset when the counter reaches a given time-out value. In normal
operation mode, it is required that the system uses the WDR - Watchdog Timer Reset - instruction to
restart the counter before the time-out value is reached. If the system doesn't restart the counter, an inter-
rupt or system reset will be issued.
Clocked from separate On-chip Oscillator
3 Operating modes
Selectable Time-out period from 1ms to 8s
Possible Hardware fuse Watchdog always on (WDTON) for fail-safe mode
Symbol
V
I
– Interrupt
– System Reset
– Interrupt and System Reset
t
BG
BG
BG
1. Values are guidelines only.
Parameter
Bandgap reference voltage
Bandgap reference start-up time
Bandgap reference current
consumption
Internal Voltage Reference Characteristics
Watchdog Timer
OSCILLATOR
128 KHz
WDP3
WDIF
WDIE
Condition
(1)
Min.
INTERRUPT
MCU RESET
Typ.
AT90PWM81
1.1
15
40
Max.
Units
µA
µs
V
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