ATA6626 ATMEL Corporation, ATA6626 Datasheet - Page 16

• Manufacturer Part Number: ATA6626
• Description: (ATA6622 - ATA6626) LIN Bus Transceiver
• Manufacturer: ATMEL Corporation

6.2
16
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Worst Case Calculation with R
ATA6622/ATA6624/ATA6626
Figure 6-1.
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 6-1.
2
1,min
2,min
wdmax
wdmin
wd
3.3V/5V
.
NTRIG
R
NRES
= 29.3 ms ±4.5 ms (±15%)
WD_OSC
VCC
120
k
34
51
91
= 0.8
= 0.8
= t
= t
1max
1min
Undervoltage Reset
t
reset
+ t
= 24.8 ms
t
Oscillator
t
1
2
Timing Sequence with R
Typical Watchdog Timings
Period
t
= 16.5 ms, t
= 17.3 ms, t
19.61
33.54
42.84
2min
osc
13.3
= 4 ms
/µs
= 16.5 ms + 17.3 ms = 33.8 ms
WD_OSC
264.80
338.22
t
154.8
wd
Lead
Time
d
1,max
105
2,max
/ms
is between the maximum t
= 51 k
= 1.2
= 1.2
t
d
= 155 ms
Window
Closed
t
t
20.64
35.32
45.11
trig
14.0
1
/ms
> 200 ns
WD_OSC
t
t
t
1
2
1
= 20.6 ms
= 24.8 ms
= 26 ms
= 51 k
Open Window
t
wd
21.67
37.06
47.34
t
wd
14.7
2
/ms
t
2
is calculated as follows.
= 21 ms
1
and the minimum t
Trigger Period from
1
t
1
Microcontroller
and t
t
64.05
29.32
50.14
wd
19.9
2
/ms
can also vary by 20%.
1
t
2
plus the minimum
4986F–AUTO–07/08
Watchdog Reset
t
nres
Reset Time
t
= 4 ms
nres
4
4
4
4
/ms