6. COMMUNICATION BETWEEN ECU‟S
•
Standard communication protocols are used.
CAN (Controller Area Network)
LIN (Local Interconnect Network)
MOST (Media Oriented Systems Transport) are a few examples.
7. FLEXRAY – THE FUTURE
•
A hybrid protocol
Time Triggered (TT) messages and Event Triggered (ET) messages
•
Consists of two segments – Static segment (ST) and Dynamic segment (DYN)
•
Uses TDMA for communication (Time Division Multiple Access)
9. SYSTEM ARCHITECTURE
•
Implemented by two schedulers.
•
Static Cyclic Scheduler
--- non-preempt tasks.
--- start time is decided at the design time or “off-line”.
•
Fixed Priority Scheduler
--- preempt tasks.
--- scheduled based priorities.
12. THE PROTOCOL
•
Communication occurs in periodic cycles
•
Each cycle consists of two intervals – ST and DYN intervals
•
ST and DYN segment lengths can be different but are fixed over the cycles.
•
Symbol Window and a network idle timer.
•
Frame Identifier
13. PAYLOAD SEGMENT
•
Slot counters – Static and Dynamic
•
Dynamic mini-slot counters
•
Node with frame identifier equal to the current slot counter is allowed to communicate.
14. CLOCK SYNCHRONIZATION
•
Backbone of FlexRay operation.
•
Clock system in a distributed system would be subject to “clock-drift”.
•
Clock drift is an inevitable inherent delay in the arrival of clock from one point to another.
•
But a global clock reference is needed to keep track of time.
•
FlexRay uses „micro-ticks” and “macro-ticks”.
•
“Cluster time” is used as a reference of global clock.
18. MODERN ELECTRONIC CONTROL UNITS
•
Energy was considered to be “freely available” until now.
•
Energy consumption is directly related to CO 2 emmission of the vehicle.
E/E Architecture
-
Partial networking.
-
AUTOSAR.
19. AUTOSAR (AUTOMOTIVE OPEN SYSTEM
ARCHITECTURE)
•
An awesome group of companies working towards delivering the best on production lines
to the world!
•
Similar to the SAE (Society of Automotive Engineers) – Another awesome group. The
biggest!
20. POWER AND ENERGY EFFICIENCY
Optimize energy consumption of electronic components.
Use of networking policies to save power and energy policies. (Communication Energy)
22. CAN – CONTROLLER AREA NETWORK
•
CSMA – Carrier Sense Multiple Access
•
Speeds up to 1 Mbps are achievable.
•
Bus topology.
•
Nothing specific in the protocol to put a node to sleep / turn-off.
•
A “sleeping” node “wakes up” if there is any activity on the bus.
•
CAN sleep object is a random sleep object.
23. FLEXRAY
•
TDMA – Time Division Multiple Access.
•
Speeds up to 10 Mbps are achievable.
•
Sleep object same as CAN.
•
Wake up is performed by sending out a specific symbol.
24. LIN – LOCAL INTERCONNECT NETWORK
•
Connects sensors and actuators.
•
One wire communication protocol.
•
Speeds up to 20kbps.
•
Master slave network is employed. One way communication. One master controls one or
more slaves. Therefore there is no need for conflict avoidance / collision.
25. MULTI-CORE MCU‟S
•
Homogeneous and Heterogeneous multi-core MCU‟s.
•
Multicore benefits.
-
Redundancy
-
Monitoring
•
Code segregation
Dedicated use of cores
Non-volatile Memory
How they originated? Engine Control UnitWhat is an Engine Control Unit? Radial enginesElectronic Control Units
Memory usually occupies the a lot of space.
Power Steering has to do with an ECU that controls a hydraulic pump that pumps hydraulic fluid when, in the direction and as much as the ECU “tells” it to in order to control the steering motion of a car. The ECU knows what has to be done by reading the steering angle on the steering wheel which is the driver input. The ECU reads this input and instructs another set of systems to provide the driver with feedback in the form of steering counterforce on the steering action
- The function of the CHI is to implement the FlexRay protocol and it is not dependent on the CPU for this. The communication controller does the job using just information form the CPU.