5 fail-safe mode – Rainbow Electronics ATA6631 User Manual
Page 11
11
9165A–AUTO–11/09
ATA6629/ATA6631
Figure 4-7.
Short Circuit to GND on the LIN bus During Sleep- or Silent Mode
4.5
Fail-safe Mode
The device automatically switches to Fail-safe Mode at system power-up. The voltage regulator
is switched on (V
CC
= 3.3V/5V/2%/50 mA) (see
). The NRES output
switches to low for t
res
= 4 ms and gives a reset to the microcontroller. LIN communication is
switched off. The IC stays in this mode until EN is switched to high. The IC then changes to Nor-
mal Mode. A power down of V
Batt
(V
S
< VS
th
) during Silent or Sleep Mode switches the IC into
Fail-safe Mode after power up. A low at NRES switches the IC into Fail-safe Mode directly. Dur-
ing Fail-safe Mode the TXD pin is an output and signals the fail-safe source.
The LIN SBC can operate in different Modes, like Normal, Silent or Sleep Mode. The functional-
ity of these Modes is described in
S
leep/
S
ilent
Mode
I
V
Ss
leep/
s
ilent
I
V
S
f
a
il
+ I
LINw
a
ke
I
V
Ss
leep/
s
ilent
V
BU
S
dom
V
LINL
LIN Pre-w
a
ke
LIN domin
a
nt
s
t
a
te
LIN BU
S
I
V
S
Mode of
oper
a
tion
Int. P
u
ll-
u
p
Re
s
i
s
tor
RLIN
off (di
sab
led)
on (en
ab
led)
W
a
ke-
u
p Detection Ph
as
e
S
leep/
S
ilent Mode
F
a
il-
Sa
fe Mode
t
mon
t
mon
Table 4-2.
TXD, RXD Depending from Operation Modes
Different Modes
TXD
RXD
Fail-safe Mode
Signalling fail-safe sources (see
Normal Mode
Follows data transmission
Silent and Sleep Mode
High
High