ATA6626(2008) Ver la hoja de datos (PDF) - Atmel Corporation

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ATA6626
(Rev.:2008)

LIN Bus Transceiver with 3.3V (5V) Regulator and Watchdog

Atmel Corporation 

5. Wake-up Scenarios from Silent or Sleep Mode

5.1 Remote Wake-up via Dominant Bus State

A voltage less than the LIN Pre_Wake detection VLINL at the LIN pin activates the internal LIN

receiver.

A falling edge at the LIN pin followed by a dominant bus level VBUSdom maintained for a certain

time period (tBUS) and a rising edge at pin LIN result in a remote wake-up request. The device

switches from Silent or Sleep Mode to Fail-safe Mode. The VCC voltage regulator is/remains

activated, the INH pin is switched to high, and the internal slave termination resistor is switched

on. The remote wake-up request is indicated by a low level at the RXD pin to generate an inter-

rupt for the microcontroller. A low level at the LIN pin in the Normal Mode starts the bus wake-up

filtering time, and if the IC is switched to Silent or Sleep Mode, it will receive a wake-up after a

positive edge at the LIN pin.

5.2 Local Wake-up via Pin WAKE

A falling edge at the WAKE pin followed by a low level maintained for a certain time period

(tWAKE) results in a local wake-up request. The device switches to Fail-safe Mode. The internal

slave termination resistor is switched on. The local wake-up request is indicated by a low level at

the RXD pin to generate an interrupt in the microcontroller and a strong pull down at TXD. When

the Wake pin is low, it is possible to switch to Silent or Sleep Mode via pin EN. In this case, the

wake-up signal has to be switched to high > 10 µs before the negative edge at WAKE starts a

new local wake-up request.

5.3 Local Wake-up via Pin KL_15

A positive edge at pin KL_15 followed by a high voltage level for a certain time period (> tKL_15)

results in a local wake-up request. The device switches into the Fail-safe Mode. The internal

slave termination resistor is switched on. The extra long wake-up time ensures that no transients

at KL_15 create a wake up. The local wake-up request is indicated by a low level at the RXD pin

to generate an interrupt for the microcontroller and a strong pull down at TXD. During high-level

voltage at pin KL_15, it is possible to switch to Silent or Sleep Mode via pin EN. In this case, the

wake-up signal has to be switched to low > 250 µs before the positive edge at KL_15 starts a

new local wake-up request. With external RC combination, the time is even longer.

5.4 Wake-up Source Recognition

The device can distinguish between a local wake-up request (Wake or KL_15 pins) and a

remote wake-up request (dominant LIN bus state). The wake-up source can be read on the TXD

pin in Fail-safe Mode. A high level indicates a remote wake-up request (weak pull up at the TXD

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

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

on the TXD pin), is immediately reset if the microcontroller sets the EN pin to high (see Figure

4-2 on page 8 and Figure 4-3 on page 9) and the IC is in Normal Mode. The last wake-up source

flag is stored and signalled in Fail-safe Mode at the TXD pin.

12 ATA6622/ATA6624/ATA6626

4986F–AUTO–07/08

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