Kia 2004.5 Spectra Service Technical Training page 279

2004.5 Spectra Technology
SRSCM/SIS COMMUNICATION
SIS INITIALIZATION
Supplemental Restraint System
The SRSCM sends command signals to the SIS and
receives response signals from the SIS.
INTERFACE
The command and response signals are separated in
time; when the SRSCM sends the clock synchronized
signal command out to the SIS, the SIS responds
when the SRSCM sends out the next command. Also,
the SRSCM command includes an address so that only
the addressed SIS will respond, again separated in
time by one command sequence (16 or 20 bit
message lengths).
As each SIS is initialized at power up, a 20-bit
command message containing address and
initialization data is sent to each SIS. During this
prove-out, the SRSCM performs an address
initialization to establish the address in a daisy-chained
application or to verify the pre-programmed non-
volatile address in the parallel application.
Once the address has been initialized, the SRSCM can
send commands to a unique SIS module on a bus and
a unique SIS module can respond to commands
directed to it. The next part of the prove-out process
consists of accelerometer initialization. Accelerometer
acceleration consists of three basic steps: status
check, bias calculation, and deflection test.
When a side impact event occurs, the SRSCM decides
whether or not the side and curtain airbags should
deploy and determines what the deployment timing
should be. This deployment decision occurs after the
Crash Severity Level from the SIS is received by the
SRSCM and compared with a signal from the
Acceleration Sensor within the SRSCM.
N N o o t t e e : : B B o o t t h h t t h h e e l l e e f f t t a a n n d d r r i i g g h h t t S S I I S S s s h h a a v v e e t t h h e e
s s a a m m e e p p a a r r t t n n u u m m b b e e r r a a n n d d h h a a v v e e l l o o c c a a t t i i n n g g t t a a b b s s f f o o r r
m m o o u u n n t t i i n n g g t t o o t t h h e e b b o o d d y y t t o o o o r r i i e e n n t t e e a a c c h h s s e e n n s s o o r r f f o o r r
t t h h e e l l e e f f t t a a n n d d r r i i g g h h t t s s i i d d e e s s . . A A f f t t e e r r s s i i d d e e / / f f r r o o n n t t a a l l
i i m m p p a a c c t t , , t t h h e e S S I I S S m m o o u u n n t t i i n n g g p p o o s s i i t t i i o o n n m m u u s s t t b b e e
i i n n s s p p e e c c t t e e d d t t o o b b e e w w i i t t h h i i n n s s p p e e c c i i f f i i c c a a t t i i o o n n . . D D i i a a g g n n o o s s i i s s
o o f f t t h h e e F F S S I I S S c c a a n n b b e e d d o o n n e e w w i i t t h h t t h h e e H H i i - - S S c c a a n n P P r r o o b b y y
c c o o d d e e r r e e t t r r i i e e v v a a l l a a n n d d K K S S I I S S f f o o r r p p r r o o c c e e d d u u r r e e s s . .
R R e e s s i i s s t t a a n n c c e e c c h h e e c c k k s s m m a a y y b b e e p p r r e e f f o o r r m m e e d d a a t t t t h h e e
F F S S I I S S a a f f t t e e r r r r e e m m o o v v a a l l f f r r o o m m t t h h e e s s y y s s t t e e m m . .
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