CAN

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Node 2 Node 3 Node 4

Node n Node 1 Ld

Ld = Drop Length

Lt

Lt = Trunk Length

ISO 11898-2 Topology

CAN

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node 1 . . . . . . . . node n

CAN Bus Line

120

CAN_H

CAN_L

120

ISO 11898-2 Network Set-up

CAN

© CiA

EMI

CAN Bus Line 120 120

CAN_H

CAN_L

t

V

Vdiff = const

Vdiff

Electromagnetic Interference

CAN

© CiA

Time

Voltage

5 V

3.5 V

2.5 V

1.5 V

0 V

min. 1 µs

Recessive

CAN_H + CAN_L

CAN_H

CAN_L

Dominant Recessive

Nominal Bus Level

CAN

© CiA

CANStation 1

(Consumer)

CANStation 2

(Producer)

CANStation 3

(Consumer)

CANStation 4

(Consumer)

Frame I

LocalIntelligence

LocalIntelligence

LocalIntelligence

LocalIntelligence

bus lines

FilterFilter Filter Filter

Broadcast Communication

CAN

© CiA

CANStation 1

(Requester)

CANStation 2

(Producer)

CANStation 3

(Consumer)

CANStation 4

(Consumer)

LocalIntelligence

LocalIntelligence

LocalIntelligence

LocalIntelligence

bus lines

FilterFilter Filter FilterRTR I Frame I

Remote Request

CAN

© CiA

CANStation 1

CANStation 2

CANStation 3

CANStation 4

LocalIntelligence

LocalIntelligence

LocalIntelligence

LocalIntelligence

bus lines

FilterFilter Filter FilterFrame I Frame 3Frame 2

Multiple Bus Access

CAN

© CiA

SOF

BusIdle

ArbitrationField

DataField

CRCField

ACKField EOF IFS

12 or 32 Bit 6 Bit 0 to 8 Byte 16 Bit 2 Bit 7 Bit1Bit 3 Bit

Remark: CAN Specification 2.0 B passive implementations can’t store or transmit Extended Data Frames; CAN Specification 2.0 B active implementations can store and transmit Standard Data Frames as well as Extended Data Frames.

ControlField

CAN Data Frame

CAN

© CiA

SOF

BusIdle

ArbitrationField

CRCField

ACKField

Inter-Mission

12 or 32 Bit 6 Bit 16 Bit 2 Bit 7 Bit1 Bit 3 Bit

ControlField EOF

CAN controller with receive buffer or receive FIFOs answers Remote Frames only under CPU control.

CAN Controller with standard message storing answers Remote Frame automatically without CPU control.

CAN Controller with advanced message storing answers Remote Frames automatically and optionally under CPU control.

CAN Remote Frame

CAN

© CiA

Base Frame Format

11 bit Identifier RTR IDE r0 DLC SOF

Arbitration Field Control Field Data Field

Extended Frame Format

SOF

Arbitration Field Control Field

11 bit Identifier SRR IDE 18 bit Identifier RTR r1 r0 DLC

Trade-off: longer bus latency time (20 bit-times)longer frames (20 bit-times plus stuff-bits)reduced CRC performance

Arbitration Field

CAN

© CiA

Node 1

Node 2

Node 3

Bus ID 20

ID 80

ID 20

Data

Data

ID 80 Data

ID 80 DataID 100 Data

ID 100 Data

Frame transmission request

Bus Arbitration Method

CAN

© CiA

Bus (4 x Rx)

S RO Identifier T Control DataF 10 9 8 7 6 5 4 3 2 1 0 R Field Field

dominant

recessive

Listening Mode

Listening Mode

Collision Avoidance

DLC Data

Listening Mode

Node 1 (Tx)

Node 2 (Tx)

Node 3 (Tx)

Node 4 (Tx)

CAN

© CiA

0 to 8 Byterequest

indication(s)

Producer Consumer(s)

CAN Data Frame

Write Object

confirmation(s)0 to 8 Byte

response

indication request(s)

CAN Remote Frame

CAN Data Frame

Read Object

Communication Services

CAN

© CiA

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 [km]

1.00.90.80.70.60.50.40.30.20.1

1.6

[Mbit/s]

Data-rate/Bus-length Ratio

CAN

© CiA

Bit Rate

1 Mbit/s800 kbit/s500 kbit/s250 kbit/s125 kbit/s

62.5 kbit/s 20 kbit/s10 kbit/s

Bus Length

30 m50 m

100 m250 m500 m

1000 m2500 m5000 m

Nominal Bit-Time

1 µs1.25 µs

2 µs4 µs8 µs

20 µs50 µs

100 µs

Practical Bus Length

CAN

© CiA

DC Parameter• Length-Related Resistance (r): 70 m /m• Termination Resistor (Rt): nominal 120 (min. 108 , max. 132 )

AC Parameter• Impedance (Z): nominal 120 (min. 108 , max. 132 )•Specific Line Delay: 5 ns/m

ISO11898-2 Parameter

CAN

© CiA

BusLength

0 .. 40 m

40 .. 300 m

300 .. 600 m

600 m .. 1 km

Bus CableLength-Related

Resistance

Bus-LineCross-Section

70 m/m 0.25 mm2 .. 0.34 mm2

AWG23, AWG22

<60 m/m 0.34 mm2 .. 0.6 mm2

AWG22, AWG20

<40 m/m 0.5 mm2 .. 0.6 mm2

AWG20

<26 m/m 0.75 mm2 .. 0.8 mm2

AWG 18

TerminationResistance

124 (1%)

127 (1%)

150

150

Max.Baudrate

1 Mbit/sat 40 m

500 Kbit/sat 100 m

100 Kbit/sat 500 m

50 Kbit/sat 1k m

DC Characteristics

CAN

© CiA

Rules of thumb for the maximum length of a unterminated cable drop Ld and for for the cumulative drop length Ldi:

n

Ld < tPROPSEG / ( 50 * tP ) Ldi < tPROPSEG / ( 10 * tP ) i=1

tPROPSEG : length of the propagation segment of the bit period tP : specific line delay per length unit

Example: bit rate = 500 kbit/s: tPROPSEG = 12 * 125ns = 1500 ns; tP = 5 ns/m n

Ld < 1500 ns / (50 * 5 ns/m) = 6 m; Ldi < 1500 ns /(10 * 5 ns/m) = 30 m i=1

Cable Drop Length

CAN

© CiA

Bit rate

Bus length (1)

Nominalbit time

tb

Number oftime quanta

per bit

Length oftime

quantum tq

Location ofsamplepoint

BTR 0at 16 MHz(82C200)

BTR 1at 16 MHz(82C200)

1 Mbit/s25 m

1 µs 8 125 ns 6 tq

(750 ns)

00h 14h

800 kbit/s50 m

1.25 µs 10 125 ns 8 tq

(1 µs)

00h 16h

500 kbit/s100 m

2 µs 16 125 ns 14 tq

(1.75 µs)

00h 1Ch

250 kbit/s250 m (2)

4 µs 16 250 ns 14 tq

(3.5 µs)

01h 1Ch

125 kbit/s500 m (2)

8 µs 16 500 ns 14 tq

(7 µs)

03h 1Ch

50 kbit/s1000 m (3)

20 µs 16 1.25 µs 14 tq

(17.5 µs)

09h 1Ch

20 kbit/s2500 m (3)

50 µs 16 3.125 µs 14 tq

(43.75 µs)

18h 1Ch

10 kbit/s5000 m (3)

100 µs 16 6.25 µs 14 tq

(87.5 µs)

31h 1Ch

CiA DS-102 Baudrate

CAN

© CiA

Pin Signal Description 1 - Reserved 2 CAN_L CAN_L bus line dominant low 3 CAN_GND CAN Ground 4 - Reserved 5 (CAN_SHLD) Optional CAN Shield 6 GND Optional Ground 7 CAN_H CAN_H bus line dominant high 8 - Reserved 9 (CAN_V+) Optional CAN external supply

9-pin D-Sub: DIN 41652

CiA DS-102 Pin Assignment

CAN

© CiA

31

203

273

355

120

2003

1998

2002

2000

2001

57 1999

40,502,6018,77 102,10

120,8214,4537,0759,2010,10

57,7710,7025,70

141,5045,4715,20

203,27

71,95171,8092,48

15,30273,82

15,70355,58

75,6045,0732-bit µC16-bit µC

stand-alone8-bit µC

total in million units

2000 sales by regions:Europe: 85%America: 9%Asia: 6%

Application

CAN node sales figures

050

100150200250300350400 32-bit µC

16-bit µC

8-bit µC

stand-alone

1999 2000 2001 2002 2003

CAN

© CiA

CAN-based Profiles

CAN-based Application Layer

Layers Implementation

Transceiver

CAN ControllerCAN Data Link Layer

CAN Physical Layer

Software

Software

CAN Reference Model

CAN

© CiA

CAN standardization

ISO 11898-1(11-bit ID)

ISO 11898-2

Data LinkLayer

PhysicalLayer

CAN 2.0A

RS-485

ISO 11898-1(11-bit ID)

ISO 11898-1(11-bit and29-bit ID)

ISO 11898-2

ApplicationLayer

SDSEN 50325-3

DeviceNetEN 50325-2

CANopenEN 50325-4

DeviceProfile

ODVADeviceProfiles

CiADeviceProfiles

ApplicationProfile

CiAApplication

Profiles

ISO 11898-2

ISO 11898-1(29-bit ID)

SAE J1939-based

ApplicationProfiles

CAN

© CiA

CAN History Milestones

• 1982: Start of the Bosch-internal CAN development• 1986: First public presentation of CAN in Detroit at SAE conference• 1987: First CAN controller chip from Intel• 1990: Introduction of CAN Kingdom protocols• 1992: Foundation of CiA international users and manufacturers group• 1993: Publishing of ISO 11898 (CAN standard)• 1993: Introduction of CAN Application Layer (CAL)• 1993: Introduction of SAE J1939 application profile• 1994: 1st international CAN Conference in Mainz• 1994: Introduction of DeviceNet• 1994: Smart Distributed System (SDS)• 1994: Introduction of CANopen profile family• 1995: Foundation of ODVA• 2000: Foundation of CAN Kingdom International• 2001: Introduction of Time-triggered CAN (TTCAN) protocol• 2002: DeviceNet, SDS, and CANopen become European standards (EN50235)• 2003: ISO 11898-1 and ISO 11898-2 are published

CAN

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CiA Operations Structure

Business Committee Managing Director Technical Committee

GENERAL ASSEMBLY

elects

CANopen

CANopen

USA

Russia

Benelux

CAL

approves and manages approves and manages

approves and manages

Inte

rest

Gro

ups

Mar

ketin

g G

roup

s

*

Progr.Devices Safety Maritime Medical Truck

Gateway

WeavingMachine

LiftControl

ElectronicDoor

PassengerInfo

IEC61131-3

GenericI/O Drive Virtual

TerminalClosed-

Loop

EncoderASAM

Railways

Off-roadVehicles Hydraulics

CA

Nop

en S

peci

al In

tere

st G

roup

s

* temporarily inactive

*

****

***

Municipalvehicles

TF BatteryTF Extruder

down-stream

TF Roadconstruct-

ion

CAN

© CiA

CiA Members 1992-2003

1642

84142

193250

284320 347

372 393 413

050

100150200250300350400450

March'92

Jan'94

Jan'96

Jan'98

Jan'00

Jan'02

CAN

© CiA

CiA Services• CANschool (technical training for newcomers) • CANopen seminar (technical training)• In-house seminars ( customer-specific training)• CANopen product guide (free-of-charge)• Quarterly CAN Newsletter (free-of-charge)• Review of proprietary CANopen profiles• CANopen device certification• CAN literature and specification sales