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© 2007 Yamar Electronics Ltd.

3

DS-ISL40 R1.6

3

OPERATION

The following paragraph describes the operation of the ISL40 device.

3.1

Protocol

The device responds to five types of LIN messages: Write, Read, Read Change, Sleep and Change

Frequency.

When receiving a Write message with the correct ID, the device outputs to its Output pins the data

indicated by the message.

When receiving a Read massage with the correct ID, the device responds to the LIN message with the

content of it’s Input pins followed by the appropriate checksum according to LIN 2.0 protocol.

When receiving a Read Change massage with the correct ID, the device responds to the LIN message

with the first detected change on its input pins followed by the appropriate checksum according to LIN

2.0 protocol.

When receiving a Sleep message the device enters into low power-consumption sleep mode. A wakeup

message generated by the master or by any of the slaves, wakes up all the devices on the network.

When receiving Change-Frequency message, the device switch between its two selected frequencies.

3.1.1

Message Construction

The construction of the five types of messages is as follows:

Write message:

The Write message consists of five bytes - sync break, sync field, Identifier, data and checksum.

The identifier byte begins with the device four ID bits, followed by 00 bits and 2 protection bits.

If checksum calculation is successful, the data byte content is transferred to the corresponding output

pins. If the device is set to 4 outputs, the four low significant bits (sent first) are transferred to the four

output SigOx pins. Otherwise, all 8 bits are transferred. The checksum is calculated according to LIN2.0

specifications. Figure 3.1 shows a generic write message.

Figure 3.1 Write message

Read message:

The read message gets the status of the ISL40 input pins.

The Read command can either get 4 input pins and 4 MSB’s of the output pins or 8 input pins status

according to the device setup pins. The Read command can request the current state of the input pins

or detect any change caused on the pins since the last read command. If the ISL40 configured to have

only 4 input pins, the 4 most significant bits of the data byte would be a read back of the 4 MSB’s output

pins.

Sync break

Sync Field

[P1, P0, 0, 1,

Address]

Out [7:0]

Checksum

ISL40 Outputs at receiving device

3 bit delay

Transmitted message