ata6616 ATMEL Corporation, ata6616 Datasheet - Page 18

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

Figure 3-8.
3.6.2
18
NTRIG
ATA6616/ATA6617 [Preliminary]
NRES
Worst Case Calculation with R
VCC
Timing Sequence with R
Undervoltage Reset
t
reset
= 4 ms
The internal oscillator has a tolerance of 20%. This means that t
The worst case calculation for the watchdog period t
The ideal watchdog time t
t
t
t
t
t
t
A microcontroller with an oscillator tolerance of ±15% is sufficient to supply the trigger inputs
correctly.
Table 3-2.
2
1,min
2,min
wdmax
wdmin
wd
.
R
= 29.3 ms ±4.5 ms (±15%)
WD_OSC
120
k
34
51
91
= 0.8
= 0.8
= t
= t
1max
1min
WD_OSC
+ t
= 24.8 ms
t
Oscillator
t
1
2
Typical Watchdog Timings
Period
t
= 16.5 ms, t
= 17.3 ms, t
19.61
33.54
42.84
2min
osc
13.3
WD_OSC
t
d
/µs
= 155 ms
= 16.5 ms + 17.3 ms = 33.8 ms
= 51 k
t
trig
= 51 k
> 200 ns
264.80
338.22
t
t
154.8
wd
Lead
Time
1
d
105
1,max
2,max
/ms
= 20.6 ms
is between the maximum t
= 1.2
= 1.2
Window
Closed
20.64
35.32
45.11
t
t
14.0
1
wd
/ms
t
t
t
1
2
2
= 21 ms
= 24.8 ms
= 26 ms
Open Window
DRAFT
47.34
t
21.67
37.06
wd
14.7
2
/ms
t
1
is calculated as follows.
1
and the minimum t
Trigger Period from
1
Microcontroller
t
and t
2
t
29.32
50.14
64.05
wd
19.9
Watchdog Reset
2
/ms
can also vary by 20%.
t
nres
1
= 4 ms
plus the minimum
9132A–AUTO–10/08
Reset Time
t
nres
4
4
4
4
/ms