Datasheet

TJA1085 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 1 — 23 October 2012 8 of 61
NXP Semiconductors
TJA1085
FlexRay active star coupler
See Ref. 1 for more details of the wake-up mechanism.
6.4.1.2 Bus wake-up via dedicated FlexRay data frame
The TJA1085 detects a wake-up event when a dedicated data frame emulating a valid
wake-up pattern, as shown in Figure 4
, is received.
The Data_0 and Data_1 phases of the emulated wake-up symbol are interrupted by the
Byte Start Sequence (BSS) preceding each byte in the data frame. With a data rate of
10 Mbit/s, the interruption has a maximum duration of 130 ns and does not prevent the
transceiver from recognizing the wake-up pattern in the payload.
For longer interruptions at lower data rates (5 Mbit/s and 2.5 Mbit/s), the wake-up pattern
should be used (see Section 6.4.1.1
).
Fig 3. Bus wake-up timing
0
V
dif
(mV)
0
-500
> t
det(wake)DATA_0
> t
det(wake)idle
> t
det(wake)idle
> t
det(wake)DATA_0
> t
det(wake)DATA_0
> t
det(wake)DATA_0
> t
det(wake)idle
> t
det(wake)idle
wake-up
+500
015aaa007
0
-500
< t
det(wake)tot
wake-up pattern
wake-up symbol wake-up symbol