ATA6661 データシートの表示（PDF） - Atmel Corporation

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ATA6661

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Atmel Corporation 

ATA6661

3.10

Mode of Operation

1. Normal mode

This is the normal transmitting and receiving mode. All features are available.

2. Sleep mode

In this mode the transmission path is disabled and the device is in low power mode.

Supply current from VBatt is typically 10 µA. A wake-up signal from the LIN bus or via pin

WAKE will be detected and switches the device to pre-normal mode. If EN, then

switches to high, normal mode is activated. Input debounce timers at pin WAKE (tWAKE),

LIN (tBUS) and EN (tsleep,tnom) prevent unwanted wake-up events due to automotive tran-

sients or EMI. In sleep mode the INH pin is floating. The internal termination between

pin LIN and pin VS is disabled to minimize the power dissipation in case pin LIN is

short-circuited to GND. Only a weak pull-up current (typical 10 µA) between pin LIN and

pin VS is present.

3. Pre-normal mode

At system power-up, the device automatically switches to pre-normal mode. It switches

the INH pin to a high state, to the VS level. The microcontroller of the application will

then confirm the normal mode by setting the EN pin to high.

4. Unpowered mode

In this mode the LIN transceiver is disabled. Data communication is switched off. If VS is

higher than VSth undervoltage threshold, the IC mode change from Unpowered to

Pre-normal mode.

3.11

Remote Wake-up via Dominant Bus State

A falling edge at pin LIN, followed by a dominant bus level maintained for a certain time period

(tBUS), results in a remote wake-up request. The device switches to pre-normal mode. Pin INH is

activated (switches to VS) and the internal termination resistor is switched on. The remote

wake-up request is indicated by a low level at pin RXD to interrupt the microcontroller (see Fig-

ure 3-2 on page 7). The voltage threshold for a wake-up signal is 3V below the VS voltage with

an output current of typical –3 µA.

3.12

Local Wake-up via Pin WAKE

A falling edge at pin WAKE, followed by a low level maintained for a certain time period (tWAKE),

results in a local wake-up request. The extra long wake-up time (tWAKE) ensures that no tran-

sient, according to ISO7637, creates a wake-up. The device switches to pre-normal mode. Pin

INH is activated (switches to VS) and the internal termination resistor is switched on. The local

wake-up request is indicated by a low level at pin RXD to interrupt the microcontroller and a

strong pull-down at pin TXD (see Figure 3-3 on page 7).

3.13

Wake-up Source Recognition

The device can distinguish between a local wake-up request (pin WAKE) and a remote wake-up

request (dominant LIN bus). The wake-up source can be read on pin TXD in pre-normal mode. If

an external pull-up resistor (typically 5 kΩ) on pin TXD to the power supply of the microcontroller

has been added, a high level indicates a remote wake-up request (weak pull-down at pin TXD)

and a low level indicates a local wake-up request (strong pull-down at pin TXD).

The wake-up request flag (signalled on pin RXD) as well as the wake-up source flag (signalled

on pin TXD) are reset immediately, if the microcontroller sets pin EN to high (see Figure 3-2 on

page 7 and Figure 3-3).

5

4729M–AUTO–02/09

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