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


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


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)


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


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


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

http://www.sae.org/

CAN FD CAPABILITIES AND USE CASES

8


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


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


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

LESSONS LEARNED AND SUGGESTIONS FOR NEW PARTS AND DEVICES

12


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


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


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

OUTLOOK

16


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)


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


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

QUESTIONS

20

Questions and comments can be turned to:[email protected]

+49-6142-763994

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February 16, 2017 (CAN FD Symposium) Harald K. Eisele, Natalie … · CAN FD FROM CONCEPT TO...

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