ATA6621 ATMEL Corporation, ATA6621 Datasheet - Page 11

• Manufacturer Part Number: ATA6621
• Manufacturer: ATMEL Corporation

3.13
3.13.1
3.13.2
3.13.3
3.14
4887B–AUTO–01/06
Wake-up Scenarios
Fail-safe Features
Remote Wake-up via Dominant Bus State
Local Wake-up via Pin Wake
Wake-up Source Recognition
A falling edge at pin LIN followed by a dominant bus level maintained for a certain time period
(T
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. The watchdog needs a trigger signal from PTRIG or NTRIG within the lead time
t
A falling edge at pin WAKE followed by a low level maintained for a certain time period (T
results in a local wake-up request. The extra long wake-up time (T
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. The watchdog needs a trigger
signal from PTRIG or NTRIG within the lead time t
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. If an external pull-up resistor (typically 5 k ) on pin TXD to the power supply of the micro-
controller 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
Figure 3-3 on page
D
• During a short circuit at LIN, the output limits the output current to I
• The reverse current at pin LIN is very low (< 3 µA) during loss of V
• During a short circuit at V
• Pin EN provides a pull-down resistor to force the transceiver into recessive mode if EN is
• Pin RXD is set floating if V
• Pin TXD provides a pull-up resistor to force the transceiver into recessive mode if TXD is
• If the WD_OSC pin has a short circuit to GND or the resistor is disconnected, the watchdog
BUS
to avoid resets at NRES.
dissipation, the chip temperature exceeds T
cools down and after a hysteresis of T
overtemperature switch-off, the V
behavior for bus systems where some slave modes are supplied from battery or ignition.
undervoltage, NRES switches to low and sends a reset to the microcontroller. The IC
switches into Pre Normal Mode. If the chip temperature exceeds the value T
output switches off. The chip cools down and after a hysteresis of T
again. Because of Pre Normal Mode, the V
switched off from the microcontroller. The microcontroller can start its normal operation.
disconnected.
disconnected.
oscillator runs with a high frequency and guarantees a reset in any condition.
) results in a remote wake-up request. The device switches to Pre Normal Mode. The V
8).
(Figure 3-2 on page
CC
Bat
, the output limits the output current to I
is disconnected.
CC
regulator works independently.
hys
, switches the output on again. During LIN
CC
LINoff
7)
voltage will switch on again although EN is
D
and the LIN output is switched off. The chip
to avoid resets at NRES.
WAKE
BAT
(Figure 3-2 on page 7
hys
BUS_LIM
VCCn
, switches the output on
or GND. This is optimal
) ensures that no tran-
. Because of
. Due to the power
ATA6621
VCCoff
, the V
WAKE
CC
and
11
CC
)