tja1082 NXP Semiconductors, tja1082 Datasheet - Page 7

• Manufacturer Part Number: tja1082
• Description: Flexray Node Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TJA1082_2
Product data sheet
6.1.1.1 Bus activity and idle detection
6.1.2 Standby mode
6.1.3 Power-off mode
6.1.4 State transitions
In Normal mode, bus activity and bus idle are detected as follows:
Standby mode is a low-power mode featuring very low current consumption. In Standby
mode, the transceiver is unable to transmit or receive data since both the transmitter and
the normal receiver are switched off. The low-power receiver is activated to monitor the
bus for wake-up activity, provided an undervoltage has not been detected on pin V
The low-power receiver is deactivated if an undervoltage is detected on pin V
result that the wake flag is not set if a wake-up pattern or dedicated data frame is
received.
Pins ERRN and RXD indicate the status of the wake flag when V
their operating ranges. See
undervoltage is detected on pin V
The status register cannot be read via the SPI interface if an undervoltage is detected on
pin V
The BGE input has no effect in Standby mode.
The transmitter and the two receivers (normal and low-power) are deactivated in
Power-off mode. As a result, the wake flag is not set if a wake-up pattern or dedicated
data frame is received. If the voltage at V
switches to Standby mode and the digital section is reset. If V
below V
The status register cannot be read via the SPI interface in Power-off mode.
Figure 4
indication signal during transitions between Normal and Standby modes, when the error
flag is set and the wake flag is not set, is illustrated in
•
•
Bus activity is detected when the absolute differential voltage on the bus lines is
higher than V
– If the differential voltage on the bus lines is higher than V
– If the differential voltage on the bus lines is lower than V
Bus idle is detected when the absolute differential voltage on the bus lines is lower
than V
staying HIGH.
IO
.
been detected, pin RXD goes HIGH.
been detected, pin RXD goes LOW.
th(det)POR
shows the TJA1082 state transition diagram. The timing diagram for the ERRN
i(dif)det(act)
, the transceiver reverts to Power-off mode (see
i(dif)det(act)
Rev. 02.03 — 10 August 2009
for t
det(idle)(bus)
Table 3
for t
det(act)(bus)
IO
. This results in pin RXD being switched HIGH or
for a description of pins ERRN and RXD when an
or pin V
CC
:
CC
rises above V
.
Figure 5
th(rec)POR
CC
FlexRay node transceiver
and described in
IL(dif)
IH(dif)
subsequently drops
IO
Section
, the transceiver
and V
after bus activity has
after bus activity has
© NXP B.V. 2009. All rights reserved.
TJA1082
6.2).
CC
are within
CC
- with the
Table
CC
7 of 35
.
6.