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© 2007 Yamar Electronics Ltd.

5

DS-ISL40 R1.6

Figure 3.5 Sleep message

Change Frequency message:

This type of message consists of 5 bytes - sync break, sync field, “FE” Hex, “00” Hex and checksum.

The change frequency message identifier is “FE” Hex and the following data byte “00”Hex.

Upon reception of sync break, sync field, “FE” Hex and “00” Hex bytes the frequency changes from F1

to F0 or vise versa.

Figure 3.6 Frequency Change message

3.2

Power Management

The device features Sleep mode for power saving. Entering Sleep and waking up are done either

locally by dedicated pins, or remotely through activity over the bus.

3.2.1

Entering Sleep mode

The ISL40 can enter sleep mode in the following ways:

1. Local device lowers its nSleep pin.

2. Remote master SIG40 device can enter the ISL40 device into Sleep Mode from Normal mode by

transmitting the remote sleep message.

3. The AutoSleep pin is high and no reception occurred for about 8 seconds.

3.2.2

Remote wake up process

The ISL40 can wakeup by a remote SIG40 master or ISL40 device transmits a wakeup message over

the bus. During Sleep Mode, the ISL40 wakes up periodically to sense the bus for activity every

32mSec. If a wakeup message is detected, the ISL40 device raises pin INH and lowers pin HDO. If

nSleep pin is low upon remote waking up, the local device that lowered it must raise the nSleep back

high. Figure 3.6 shows the signals description.

Figure 3.7 - Wakeup from bus message

3.2.3

Wakeup from pin Wake

A transition on pin Wake (caused by an external switch of the application) is used to wake the device.

The device then enters Standby mode, raises pin INH, and transmits a wakeup message to the bus.

While transmitting the wakeup message to the bus, the device lowers pin HDO. After the transmission

is complete the device raises pin HDO. After the transmission is completed the device enters Normal

Sync break

Sync Field

0x3C

Zero byte/bytes

Checksum

INH

msg. detected

DC-BUS

Wakeup Message

HDO

Standby

Sync break

Sync Field

0xFE

Zero byte/bytes

Checksum