33689D datasheet(23/31 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

33689

FUNCTIONAL DESCRIPTION

FUNCTIONAL DEVICE OPERATION

NORMAL MODE

In Normal Mode, the 33689 has slew rate and timing

compatible with the LIN protocol specification. The LIN bus

can transmit and receive information. The VDD regulator is

ON and the watchdog function can be enabled.

SLEEP AND STOP MODE

To safely enter Sleep or Stop modes and to ensure that

these modes are not inadvertently entered due to noise

issues during SPI transmission, a dedicated sequence must

be sent twice: data with the bits controlling the LIN bus and

the device mode.

Entering Sleep Mode

First and second SPI commands (with bit D6=1, D7=1,

D5 =0 or 1, D1=0, and D0=0) 11x00000 must be sent.

Entering Stop Mode

First and second SPI commands (with bit D6=1, D7=1,

D5 =0 or 1, D1=0, and D0=1) 11x00001 must be sent.

Sleep or Stop modes are entered after the second SPI

command. Register bit D5 must be set accordingly.

Table 1. Operational Modes and Associated Functions

Device Mode

VDD Voltage

Regulator

Wake-Up

Capabilities

RST

Output

Watchdog

Function

HS1, HS2, HS3

LIN Interface

Operational

Amplifier

Reset

VDD: ON

N/A

LOW for 1.0 ms

typical, then

HIGH (if VDD

above threshold)

Disabled

OFF

Recessive only

Not active

Normal

Request

VDD: ON

N/A

HIGH.

Active LOW if

VDD

undervoltage

occurs and if

Normal Request

timeout (if

Watchdog

enabled)

150 ms timeout

if Watchdog

enabled

ON or OFF

Transmit and

receive

Not active

Normal

VDD: ON

N/A

HIGH.

Active LOW if

VDD

undervoltage

occurs or if

Watchdog fail (if

Watchdog

enabled)

Window

Watchdog if

enabled

ON or OFF

Transmit and

receive

Active

Stop

VDD: ON

(Limited current

capability)

LIN and state

change on

L1:L2 inputs

Normally HIGH.

Active LOW if

VDD

undervoltage

occurs

Disabled

OFF

Recessive state

with Wake

capability

Not active

Sleep

VDD: OFF

(Set to 5.0 V

after Wake-Up

to enter Normal

Request)

LIN and state

change on

L1:L2 inputs

LOW.

Go to HIGH after

Wake-Up and

VDD within

specification

Disabled

OFF

Recessive state

with Wake

capability

Not active

33689D Datasheet(PDF) 23 Page - Freescale Semiconductor, Inc

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