tja1080 NXP Semiconductors, tja1080 Datasheet - Page 43

• Manufacturer Part Number: tja1080
• Description: Flexray Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TJA1080_2
Product data sheet
15.1.2 Bus error detection when transmitting a wake-up pattern
15.1.3 Receiver signal
Consequences of an improper power-up sequence
In case of an improper initialization due to ramping up V
may happen that a TJA1080 transceiver applied for star configuration may come up in
node configuration.
The other way around, erroneous configuration in star configuration, while the transceiver
is applied as node transceiver, has not been observed, however it is strongly
recommended to apply the power-up sequence also to node transceivers.
Furthermore, due to improper initialization, it can occur that ERRN becomes clamped to
permanent LOW in both node and star configuration.
Work around
There is no work around for this issue. To ensure a proper device initialization the correct
power-up sequence has to be applied.
The TJA1080 expects a data frame that begins with a bit value different from the last bit of
the previous data frame.
This is the case for a valid data frame, which begins with the DATA_0 period of the
Transmission-Start-Sequence (TSS) and ends with the DATA_1 bit of the Frame-End-
Sequence (FES).
Any violation of this frame format will be detected by the TJA1080. Consequently when
transmitting a wake-up pattern, a bus error will be signaled.
Consequences
This behavior of the TJA1080 is not conform to the FlexRay Electrical Physical Layer
specification [1]
Work around
The error indication when a wake-up pattern is transmitted should be ignored and the
status register should be cleared by reading the vector.
The delay time and delay time difference from bus to RXD (see
of 80 ns and a receiver test signal of 600 mV differential bus level (see
receiver test signal is not conform to the FlexRay Electrical Physical Layer
specification (see
Consequence
If the differential bus level becomes lower than 600 mV, the delay time difference from bus
to RXD (t
t
d(bus-RXD)
d(bus-RXD)
, t
d(bus-TRXD)
Ref.
) can become higher than 5 ns.
, t
1).
Rev. 02 — 12 July 2007
d(bus-TRXD)
) is guaranteed in the TJA1080 for a minimum bit time
BAT
and V
Table
CC
FlexRay transceiver
simultaneously, it
15: t
Figure
© NXP B.V. 2007. All rights reserved.
TJA1080
d(bus-RXD)
11). This
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