ETAS ES800 - Application Examples; Bus Termination Resistor; Flexray Interface (FLX); Properties

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ETAS ES800 System | User Guide
12.6 FlexRay Interface (FLX)
The CAN / FLX interface of the ES891.x module can optionally be operated as CAN
FD interface or as FlexRay interface.
In the FlexRay operating mode, the two FlexRay channels FLX1 and FLX2 are avail-
able with separate connections. The interfaces are electrically isolated from each
other and from the other interfaces.
12.6.1 Properties
The FlexRay applications supported by the module are listed in an overview in
chapter 16.9.8 on page 159.
12.6.2 Bus Termination Resistor
The FlexRay specification allows the design of different bus topologies, such as
passive bus, passive star or active star. Each of the topologies requires a corre
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sponding bus termination. The FlexRay termination selected by ETAS in the con-
text of the FlexRay specification measures 100 ohm. To support the design in
FlexRay networks, ETAS offers FlexRay cables and matching FlexRay terminations.
The terminations must be connected to the cable or the plug.
12.6.3 Synchronization Nodes
After the start of a FlexRay network, the local clock generators of all nodes of the
network must be synchronized. Prerequisites for the synchronization process are
at least two nodes that can send sync frames (synchronization node). The other
nodes of the network synchronize themselves by analyzing the occurrence of the
sync frame and adjusting their local clock generator.
The FlexRay interface is equipped with an additional internal synchronization
node. The synchronization node can take over only synchronization functions and
is internally connected with the FlexRay channels FLX1 and FLX2. If this synchroni
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zation node sends Start-up/Sync messages as the second node of the FlexRay
network, then FlexRay networks in which no other nodes with synchronization
module exist can be started and synchronized with a single ES89x module.
12.6.4 Application Examples
Testing/starting up FlexRay ECUs outside of FlexRay networks
- Flashing ECUs via FlexRay
- Display of function state of FLX interface
NOTE
On delivery, the ES891.x CAN/FLX interface is configured for the CAN operating
mode. The operating mode is selected in the web interface of the module.
After every change of the operating mode of the interface between CAN and
FlexRay, a restart of the system is required.