ata6603 ATMEL Corporation, ata6603 Datasheet - Page 16

• Manufacturer Part Number: ata6603
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

3.3.18
3.3.18.1
16
ATA6602/ATA6603
Watchdog
Typical Timing Sequence with R
Figure 3-9.
For programming purposes at the microcontroller it is potentially necessary to supply the VCC
output via an external supply while the VS pin of the system basis chip is disconnected. This
behavior is no problem for the system basis chip.
The watchdog anticipates a trigger signal from the microcontroller at the NTRIG (negative edge)
or the PTRIG (positive edge) input within a period time window of T
exceed a minimum time t
generated at output NRES. The timing basis of the watchdog is provided by the internal oscilla-
tor, of which the time period t
In Silent or Sleep mode, the watchdog is switched off to reduce current consumption.
Minimum time for first watchdog pulse is required after the undervoltage reset at NRES disap-
pears and is defined as lead time t
The trigger signal T
For example, with an external resistor of R
watchdog come out as follows:
t
t
t
t
t
After every reset the watchdog always starts with the lead time.
OSC
d
1
2
nres
= 3922
= 800
= 840
= 157
= 12.5 µs due to 51 k
12.5 µs = 10 ms
12.5 µs = 10.5 ms
12.5 µs = 49 ms
12.5 µs = 1.96 ms
Power Dissipation: Safe Operating Area versus V
Voltage V
wd_osc
wd
is adjustable between 2.9 ms and 33 ms via the external resistor R
40
30
20
50
45
35
25
55
10
15
0
S
5
= 51 k
trigmin
5
at Different Ambient Temperatures T
osc
6
> 3 µs. If a triggering signal is not received, a reset signal will be
is adjustable via the external resistor R
7
d
.
8
9
10
wd_oscSC
11
V
S
12
(V)
= 51 k ±1%, the typical parameters of the
13
14
15
case
DD
16
125˚C
105˚C
with R
Output Current and Supply
17
wd
. The trigger signal must
wd_osc
18
thJA
19
= 35 K/W
(10 k to 120 k ).
4921D–AUTO–08/07
wd_osc
.