ATA6824-MFHW Atmel, ATA6824-MFHW Datasheet - Page 8

• Manufacturer Part Number: ATA6824-MFHW
• Description: IC MOTOR DVR H-BRIDGE 32TPQFP
• Manufacturer: Atmel

Specifications of ATA6824-MFHW

• Applications: DC Motor Controller
• Number Of Outputs: 1
• Voltage - Supply: 6.5 V ~ 21.3 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.3.1
8
Atmel ATA6824
Timing Sequence
For example, with an external resistor R
ters of the watchdog.
T
The times t
After ramp-up of the battery voltage (power-on reset), the V
reset output, /RESET, stays low for the time t
t
window watchdog sequence. If no rising edge is detected, the watchdog will reset the micro-
controller for t
Times t
receiving a reset from the watchdog, the triggering signal from the microcontroller must hit the
timeframe of t
Figure 5-4.
If triggering fails, /RESET will be pulled to ground for a shortened reset time of typically 2ms.
The watchdog start sequence is similar to the power-on reset.
The internal oscillator is trimmed to a tolerance of < ±10%. This means that t
vary by ±10%. The following calculation shows the worst case calculation of the watchdog
period T
t
t
T
T
T
Figure 5-4 on page 8
external resistor R
A reset will be active for V
(HYS
d
1min
2min
OSC
wdmax
wdmin
wd
(for setups in the controller) the watchdog waits for a rising edge on WD to start its normal
= 16.42ms ±3.15ms (±19.1%)
= 0.90
= 0.90
= 12.32µs, t
RESth
= t
= t
1
wd
(close window) and t
1max
1min
).
which the microcontroller has to provide.
res
+ t
= 13.28ms
res
2
= 70ms and t
t
t
1
2
T
= 9.61ms. The trigger event will restart the watchdog sequence.
WD
= 10.87ms, t
= 8.65ms, t
2min
and wait t
1
OSC
= 12.1ms, t
versus R
= 10.87ms + 8.65ms = 19.52ms
.
shows the typical watchdog period T
60
40
30
20
50
10
0
10
d
d
2max
for the rising edge on WD.
WD
= 70ms are fixed values with a tolerance of 10%.
1max
CC
2
20
2
(open window) form the window watchdog sequence. To avoid
= 9.61ms, T
= 1.10
< V
= 1.10
30
tHRESx
40
WD
t
2
t
; the level V
1
= 10.57ms
WD
= 33k ±1% we get the following typical parame-
= 13.28ms
res
50
RWD (k )
= 16.88ms ±10%
, then switches to high. For an initial lead time
60
max
tHRESx
70
min
WD
CC
80
depending on the value of the
is realized with a hysteresis
regulator is switched on. The
90
typ
100
1
and t
4931L–AUTO–02/11
2
can also