ATA6621N-PGPW(2007) Ver la hoja de datos (PDF) - Atmel Corporation

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ATA6621N-PGPW
(Rev.:2007)

LIN Transceiver with 5V Regulator and Watchdog

Atmel Corporation 

ATA6621N

3.15.6

Debug Mode

The watchdog is switched off with pin MODE high (5V) and in normal operation if it is tied to

GND (see Figure 5-2 on page 24).

Table 3-1. Table of Modes

Mode of

Operation

Transceiver

Pre-normal

Off

Normal

On

Silent

Off

Sleep

Off

VCC

5V

5V

5V

0V

WD_OSC

2.5V

2.5V

0V

0V

TEMP

2V

2V

0V

0V

RXD

5V

5V

5V

0V

LIN

RECESSIVE

RECESSIVE

RECESSIVE

RECESSIVE

3.16 Wake-up Scenarios from Silent or Sleep Mode

3.16.1

3.16.2

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. The VCC

voltage regulator is activated, and the internal slave termination resistor is switched on. The

remote wake-up request is indicated by a low level at pin RXD to generate an interrupt in the

microcontroller and a high level at pin TXD. The watchdog needs a trigger signal from PTRIG or

NTRIG within the lead time tD to avoid resets at NRES. (Figure 3-3 on page 8)

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-

sients as defined in ISO7637 create a wake-up. The device switches to Pre-normal mode. The

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

level at pin RXD to generate an interrupt in the microcontroller and a low level at pin TXD. The

watchdog needs a trigger signal from PTRIG or NTRIG within the lead time tD to avoid resets at

NRES.

3.16.3

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 state). The wake-up source can be read on pin TXD in Pre-normal

mode. A high level indicates a remote wake-up request and a low level indicates a local wake-up

request. 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 (Figure

3-3 on page 8).

If the ATA6621N is in Sleep mode or Silent mode and the voltage at the LIN Bus falls to a value

lower than VLINL < VS – 3.3V) (see “Electrical Characteristics” numbers 9.5 and 9.6) but

remains higher than 0.6 × VS, a local wake-up is indicated after the time tWAKE by a low level at

the pins RXD and TXD (Figure 3-6 on page 12).

11

4887H–AUTO–12/07

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