AT90CAN128-16AE ATMEL Corporation, AT90CAN128-16AE Datasheet - Page 54

• Manufacturer Part Number: AT90CAN128-16AE
• Description: 8-bit Avr Microcontroller With 128K Bytes of Isp Flash And CAN Controller.flash (Kbytes) 128 Vcc (V) 2.7-5.5 EEPROM (Kbytes) 4 SRAM (bytes) 4K CAN (mess. Obj.) 15
• Manufacturer: ATMEL Corporation

Voltage Reference
Characteristics
Watchdog Timer
54
AT90CAN128
Table 22. Internal Voltage Reference Characteristics
Note:
The Watchdog Timer is clocked from a separate On-chip Oscillator which runs at
1 MHz. This is the typical value at V
at other V
interval can be adjusted as shown in Table 24 on page 55. The WDR – Watchdog Reset
– instruction resets the Watchdog Timer. The Watchdog Timer is also reset when it is
disabled and when a Chip Reset occurs. Eight different clock cycle periods can be
selected to determine the reset period. If the reset period expires without another
Watchdog Reset, the AT90CAN128 resets and executes from the Reset Vector. For tim-
ing details on the Watchdog Reset, refer to Table 24 on page 55.
To prevent unintentional disabling of the Watchdog or unintentional change of time-out
period, two different safety levels are selected by the fuse WDTON as shown in Table
23. Refer to “Timed Sequences for Changing the Configuration of the Watchdog Timer”
on page 56 for details.
Table 23. WDT Configuration as a Function of the Fuse Settings of WDTON
Figure 28. Watchdog Timer
WDTON
Unprogrammed
Programmed
Symbol
V
t
I
BG
BG
BG
1. Values are guidelines only.
CC
Parameter
Bandgap reference voltage
Bandgap reference start-up time
Bandgap reference current
consumption
levels. By controlling the Watchdog Timer prescaler, the Watchdog Reset
Safety
Level
1
2
OSCILLATOR
WATCHDOG
WDT Initial
State
Disabled
Enabled
CC
= 5V. See characterization data for typical values
Condition
How to Disable the
WDT
Timed sequence
Always enabled
(1)
Min.
TBD
Typ.
TBD
TBD
TBD
How to Change
Time-out
Timed sequence
Timed sequence
Max.
TBD
TBD
4250C–CAN–03/04
Units
µA
µs
V