Mitsubishi Evolution X. Manual — part 114

54B-1

GROUP 54B

LOCAL

INTERCONNECT

NETWORK (LIN)

CONTENTS

GENERAL INFORMATION . . . . . . . .

54B-2

STRUCTURE . . . . . . . . . . . . . . . . . . .

54B-2

SYSTEM OPERATION . . . . . . . . . . . .

54B-3

GENERAL INFORMATION

TSB Revision

LOCAL INTERCONNECT NETWORK (LIN)

54B-2

GENERAL INFORMATION

M2545600100064

LIN refers to "Local Interconnect Network," which is a
serial multiplex communication protocol

*

adminis-

trated by LIN consortium. A communication circuit
employing the LIN protocol connects each ECU, and
switch and sensor data can be shared among ECUs,
which enables more reduction in wiring.

NOTE:

*

: The regulations that have been decided in

detail, from software matters such as the necessary
transmission rate for communication, the system,
data format, and communication timing control
method to hardware matters such as the harness
type and length and the resistance values.

STRUCTURE

M2545600200180

Master and slave ECUs are connected to the LIN
bus lines. The master ECU is the ETACS

*1

-ECU,

and the slave ECUs are the column switch (col-
umn-ECU), the power window main switch, the sun-
roof-ECU

*2

and the lighting control sensor

*3

. The

master ECU requests these slave ECUs to commu-
nicate each other via communication lines.

NOTE:

.

•

*1

: ETACS (Electronic Time and Alarm Control

System)

•

*2

: Vehicles with sunroof

•

*3

: Vehicles with auto light function

AC708922 AB

ETACS-ECU

Master ECU

Column switch
(column-ECU)

Sunroof motor
assembly
(Sunroof-ECU)*

1

Note:
*

1

: Vehicles with sunroof

*

2

: Vehicles with auto light function

Lighting control
sensor*

2

Slave ECU

Slave ECU

Slave ECU

Slave ECU

LIN bus line

Power window
main switch

SYSTEM OPERATION

TSB Revision

LOCAL INTERCONNECT NETWORK (LIN)

54B-3

SYSTEM OPERATION

M2545600300068

.

LIN communication system is described below:

• The master ECU performs the master tasks and

slave tasks, and the slave ECUs perform the
slave tasks.

• When the master ECU performs a master task,

the header frame which stores information to call
certain slave tasks (ECU) is transmitted at regular
intervals.

• When the master ECU and slave ECU perform a

slave task, the ECU called by the header frame
transmits the response frame which stores data
used for control.

• A header and response collectively are called as

a message frame, and the communication
method that uses the message frame is called as
the frame communication.

• Basically, the communication data is used with

some blocks of 10-bit data group which includes
one start bit and one stop bit (byte region)
arranged in order.

.

AC506324

AC506324

Master ECU

AB

Slave ECU

Slave ECU

Slave task A

Slave task B

Master task

Slave task D

Slave task C

LIN bus line

State of message on LIN bus line

<Master task>

<

Slave task

>

Response

Slave task D

Time

Header

Transmits the header
at regular intervals.

Transmits the response
to suit the header

Byte area

Theory value:

1

0

Start bit

Stop bit

Data bit

1 byte

Slave task A

Slave task C

Slave task B

Response

Header

Response

Header

Response

Header

SYSTEM OPERATION

TSB Revision

LOCAL INTERCONNECT NETWORK (LIN)

54B-4

VOLTAGE VARIATION OF LIN BUS LINE

When each ECU sends or receives signals, LIN bus
line voltage varies as follows:

• The voltage variation of LIN bus line (0 and 1

combination as a theoretical value) ranging
between battery voltage (recessive) and 0 V
(dominant) is output (transmitted) as a control
signal.

• When no communication is established, the LIN

bus line remains recessive (battery voltage).

.

MESSAGE FRAME

A message frame consists of regions that include a
synchronization start region, identifier region, data
region, and checksum region. A few bits of recessive
data is used to separate the frame from each region.

AC309813

Voltage variation of
LIN bus line:

State:

Theoretical value:

Battery voltage

GND

(Ground level)

Recessive

Dominant

Recessive

1

0

AD

AC506907

Message frame

Header

Response

a

b

c

d

e

AB

d

d

a: Synchronization start region

b: Synchronization region

c: Identifier region

d: Data region

e: Checksum region

Theoretical value:

1 (Recessive)

0 (Dominant)