February 16, 2017 (CAN FD Symposium) Harald K. Eisele, Natalie … · CAN FD FROM CONCEPT TO...
Transcript of February 16, 2017 (CAN FD Symposium) Harald K. Eisele, Natalie … · CAN FD FROM CONCEPT TO...
CAN FD FROM CONCEPT TO PRODUCTION
February 16, 2017 (CAN FD Symposium)
Harald K. Eisele, Natalie A. Wienckowski
Harald K. EiseleNatal ie Wienckowski17/02/16
AGENDA
2
• CAN FD - How the success story began
• High-level technology rollout
• Standardization update / high-level introduction to SAE J2284
• How to make best use of CAN FD
• Lessons learned
• Suggestions for new devices and parts
• Summary
Harald K. EiseleNatal ie Wienckowski17/02/163
EVOLUTIONARY TECHNOLOGY GROWTH
2011 challenge: How can automotive system owners get
• More data throughput
• Enhanced data cohesion
• Enhanced diagnostic coverage
Without network topology changes and while being able to re-use newhardware in legacy systems?
Solution idea: Use higher bit rate in those parts of a CAN messagewhere only a single transmitter is supposed to be active
Harald K. EiseleNatal ie Wienckowski17/02/164
HIGH-LEVEL CAN FD TECHNOLOGY ROLLOUT
2012 2013 2014 201720162015
Series development at several automakers
CAN FD standardization
Semiconductor product designs consider CAN FD
SAE J2284-5 5 Mbps
SAE J2284-4 2 Mbps
Physical Layer Standard ISO 11898-2 (2016)
Software
Bus nodes / ECUs
Microcontrollers
Bus transceivers
AUTOSAR R4.2.1CAN FD 64 databytes
ISO CAN FD format (with stuff count)
Non-ISO CAN FD format
AUTOSAR R4.1.1CAN FD 8 databytes
Bit error detection weaknessidentified and fixed
Data Link Layer Standard ISO 11898-1 (2015)
Bosch: Initial busprotocol
specification
GM: More bandwidth
needed
Transport ProtocolISO 15765-2 (2016)
Harald K. EiseleNatal ie Wienckowski17/02/165
CAN PHYSICAL LAYER AND DATA LINK LAYER STANDARDS
CAN Components / Parts / ICsRequirements Conformance Test Plan
Bus Nodes / Electronic Devicescontrol units, sensors, displays
Physical Layer ISO 11898-2 (2016) ISO 16845-2 (2017) SAE J2284-1 (NOV 2016)SAE J2284-2 (NOV 2016)SAE J2284-3 (NOV 2016)SAE J2284-4 (JUN 2016)SAE J2284-5 (SEP 2016)
Data Link Layer ISO 11898-1 (2015) ISO 16845-1 (2016)
Examples for physical layer changes• AC parameters for 2 Mbps and 5 Mbps specified• For PN parts: Tolerance to CAN FD format specified• Bus output level at arbitration specified• Extended differential load range defined• Output short circuit current specified• Transmit timeout defined• Maximum ratings modified/extended
Examples for what is specific to SAE J2284• Bit rates and bit timing details specified• Bus node operating voltages specified• Communcation resume latency specified• Extended differential load range mandatory
except for J2284-5• EMC requirements specified• Fault behavior defined
PN = Partial Networking
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VOLTAGE ILLUSTRATION FOR ISO CAN PHYSICALLAYER STANDARD, EDITION 2016
18V Absolute bus linevoltage
-27V 40V
-2V 0 7V
-3V
12V-12V
Differential bus voltage
8V
10V
-5V
-3V
No damage tobus transceiverBus receiver
functional
Defined short-circuitoutput current
Transmitter output level range
5V
RX
2016 edition of ISO 11898-2 makesCAN physical layer fit for near futurehigh driving automation levels
5V
TX
Defined businput resistance
Harald K. EiseleNatal ie Wienckowski17/02/167
SAE J2284 CAN STANDARDS
J2284-1revised
J2284-2revised
J2284-3revised
J2284-4new
J2284-5new
Frame Formats Classical CAN only
Classical CAN only
Classical CAN only
CAN-FD andClassical CAN
CAN-FD andClassical CAN
CAN data bit rate [Mbit/s]
0.125 0.25 0.5 Data phase: 2Arbitration: 0.5
Data phase: 5Arbitration: 0.5
Number of bus nodes 32 32 24 24 2
Partial Networking (selective wakeup)
Optional Optional Optional Optional N/A
Minimum number oftime quanta per bit
12 16 16 Arbitration: 40Data phase: 10
Arbitration: 80Data phase: 8
Stub length [m] 1.7 1.7 1.7 1.7 n/a
Publication date NOV 2016 NOV 2016 NOV 2016 JUN 2016 SEP 2016
www.sae.org
Harald K. EiseleNatal ie Wienckowski17/02/16
1.5
2.12.6
2.8 3.0
2.0
3.2
4.1
4.65.1
2.5
4.3
5.7
6.8
7.7
2.8
5.2
7.2
8.9
10.5
0.0
2.0
4.0
6.0
8.0
10.0
12.0
1 2 3 4 5
Typical CAN FD net data bandwidth compared to Classical CAN 500 kbit/s, 8 bytes
8 16 32 64
9
EFFECT OF MESSAGE PACKING AND CAN FD DATAPHASE BIT RATE
Today: Classical CAN 500 kbit/s 8 bytes per message
1.0
Typical relative netbandwidth (data bytes/ms) compared to Classical CAN
SAE J2284-424 nodes
SAE J2284-52 nodes
11 bit headerarbitration bit rate 500 kbit/s
Note: Short bitsimpose constraintson network topology
For an 8 byte message, a data length change to16 bytes accommodatesmore bandwidth compareddoubling the data phasebit rate
SAE J2284-5 / 64 bytemessages accommodate~ 10x the bandwidth ofClassical CAN 500 kbit/s
CAN FD data phase bit rate (Mbit/s)
Bytes per message
Harald K. EiseleNatal ie Wienckowski17/02/1610
CAN FD USE CASES
• Device Programming and Diagnostics
• Body controls, Infotainment controls
• Powertrain controls
• Vehicle dynamics controls
Steering ECU
Engine ECU
Braking ECU
CAN FD Data at 2 Mbit/sSAE J2284-4 / ISO 11898-1
Full Automation
Driver Assistance
Partial Automation
ConditionalAutomation
High Automation
No automation
CAN_A CAN_B
Driving automation levelsacc. to SAE J3016
Depending on thedriving automationlevel, fallbackcapability will benecessary forelectrical systems
High-level near-future data communication needs• Defined behavior, also when defined faults
present• For defined subnets: Detection of unexpected
network usage• For defined messages in defined subnets:
Limited bus latency and messageauthentication
Harald K. EiseleNatal ie Wienckowski17/02/1611
HIGH-LEVEL NEAR FUTURE NETWORK TOPOLOGY
Off-boardtester
On-board gateway or backbone
A
CAN FD capable mC
PNXCVR
B C D
SAE J2284-5CAN FD 5 MbpsNon-PN / wakeup on any message
SAE J2284-4CAN FD2 Mbps
SAE J2284-4CAN FD2 Mbps
SAE J2284-3Classical CAN500 kbps
SAE J2284-3Classical CAN500 kbpsSAE J2284-3
Classical CAN500 kbps
E
PN = Partial NetworkingXCVR = Transceiver
XCVR
CAN orCAN FD
capable mC
Protocols other than CAN not shown on this page
Device activation typically controlled by CAN bus message data content
PNXCVR
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CAN FD LESSONS LEARNED
• Bit timing variations have more effect on CAN FD compared toClassical CAN. For best performance the BRS bit needs to havesame length for all nodes in a subnet
• Ringing has more impact on CAN FD because data bits are shorter• Long cable stubs increase ringing
• Common-mode chokes increase ringing
• Lower dielectric cable insulation reduces ringing
BRS = Bit Rate Switch
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SUGGESTIONS FOR CAN TRANSCEIVERS
• New parts should be consistent to ISO 11898-2 (2016) andSAE J2962-2
• Extended bus differential load range (45 to 70 Ohms)
• Transmit dominant timeout
• Transceivers should consume less than or equal to 30 mA in sleepmode when bus traffic absent
• Partial networking products Capable to treat reserved bit after a recessive FDF bit is also recessive as error
When mC does not respond to transceiver’s attempt to wake it up, the transceiver should transition back to frame detect (traffic present) or sleep mode (traffic absent) after a defined time period
CAN FD Data Phase Bit Rates
• 5 Mbps Capable of bus wakeup on pattern according to ISO 11898-2 (2016)
No wakeup on single bus signal edge
• 2 Mbps Capable of sleeping while CAN-FD traffic present according to SAE J2284-4
Capable of CAN message data control led bus wakeup (partial networking)
FDF = FD Format
Harald K. EiseleNatal ie Wienckowski17/02/1615
SUGGESTIONS FOR CAN CONTROL UNITS / DEVICES
• Consider 2016 releases of SAE J2284 in devices / ECU designs *
• Data security enhancements / Intrusion detection enhancements
In some cases
• Precise common notion of time
• For defined messages: Message authentication and limited buslatency / real-time enhancements
* Note: For bus input resistance, the voltage range specified in ISO 11898-2 (2016) is sufficient, i.e. -2V to +7V
Harald K. EiseleNatal ie Wienckowski17/02/1617
CONSOLIDATION OF AUTOMOTIVE DATA COMMUNICATION PROTOCOLS/LINKS
CAN (FD)
MOST
Automotive Ethernet
FlexRay
CAN 2.0
Present Future
Low-bandwidth protocols not shown on this page
LVDS
SAE J2284-3: Classical CAN 500 kbit/s
SAE J2284-4: 2 Mbit/s with arbitration bit rate 500 kbit/s
SAE J2284-5: 5 Mbit/s with arbitration bit rate 500 kbit/s
100BASE-T1 (100 Mbit/s)
1000BASE-T1 (1 Gbit/s)
IEEE 802.3 (> 1 Gbit/s)
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ETHERNET USE CASES
• Diagnostics and programming
• AVB: Infotainment
• TSN: Seamless redundancy or/and high-bandwidth real-time
• TSN: Data communication backbone
AVB = Audio Video Bridging
TSN = Time Sensitive Networking
Harald K. EiseleNatal ie Wienckowski17/02/1619
SUMMARY
• Automotive features will continue to grow, increasing demands on communication network resources (bandwidth, security, dependability)
• CAN FD is a technology that is suitable for the next generation electrical architecture because it supports above improvements while preserving investments made
• CAN FD and Automotive Ethernet (AVB, TSN) will co-exist in next generation systems
AVB = Audio Video Bridging
TSN = Time Sensitive Networking