CAN BUS

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1 CAN BUS CAN-BUS No! It's something different... CAN = Controller Area Network 智能設備的區域網路多數汽車的主要網路傳感器數值的作動分析

2 什麼是推動 CAN 區域網路的動力? 簡化導線減輕線組更高的系統靈活性改善廢氣排放數值增加系統傳送負載跨系統訊息的交換統合故障診斷系統系統建構整合容易 CAN bus 的主要特徵廣域多主系統的控制能力內含可確認優先權的標準識別符號持續性自動廣播系統參加者的同步數據安全性不正常的訊息的察覺和改正

3 CAN History Timeline 5.. CAN controllers sold * More than 8 different controllers available from 9 manufacturers CAN in Automation (CiA) founded International CAN manufacturers and users organization First specification of the CAN Protocol *Source: CAN in Automation (CiA) e.v Tim e ISO 898 standardization World-wide standardization leads to the widespread use of CAN in mass-market applications, e.g. automobiles First CAN Controller on the market: Intel 82C526 BOSCH starts developing the CAN Protocol Intended use: Power train applications

manufacturers and users organization http://can-cia.de First specification of the CAN Protocol *Source: CAN in Automation (CiA) e.v.

4 CAN Introduction(CAN 簡介 ) What is CAN? CAN 是一種支持分散式產品及分散式系統架購之公共小型區域網路之解決方案 CAN bus 的作用是使網路節點或模組相互連結, 一般是採用雙絞線連結網路包含汽車, 卡車, 巴士, 農業, 船舶, 營建, 醫療, 工廠自動化, 紡織及其它多種工業都有使用典型的 CAN 協定依據 ISO 7498 定義了 7 個獨立階層協定堆疊參考模型, 但 CAN 協定並不需分割成 7 個階層 (Bosch CAN 2.B 允許位元及 29 位元識別字共用同一匯流排 ) The ISO/OSI seven-layer model Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Electronic Control Unit Applications, operating system Conversion of data formats Task synchronization, buffers, connection setup and monitoring, access rights control Address conversion, routing, segmentation Setup of logical connection, transport protocol Transmission security, frame setup, error management Electrical / mechanical characteristics: Transmission medium, wiring, connectors, encoding, signals OSI Seven Layer Description (OSI 7 個階層描述 )

5 OSI Seven Layer Description (OSI 7 個階層描述 ) Physical 實體層著重於已組織之位元流的傳送, 處理有關實體媒介機械的, 電子的, 功能性的及程序性的特性 Data Link 資料連結層提供資訊跨越實體層時可靠的傳送, 送出具有錯誤控制, 同步, 資訊流控制之封包 ) Network 網路層 : 提供較高一層之系統連接, 有別於資料傳輸與交換技術 Transport 傳輸層提供端點間可靠, 通透的資料傳輸 ; 提供端對端, 錯誤復原及資訊流控制 Session 會議層提供應用, 建制, 管理以及協同應用間連線的終止之通訊控制架構,CAN 不採用 Presentation 演示層 : CAN 不採用 Application 應用層提供使用者存取 OSI 環境及提供分散式資訊服務, 使用者應用程式及 OBD 服務位於此層 CAN Data Frames CAN 2.A (Standard Format) ( 標準格式 ) - 位元訊息識別字 - 只傳遞及接收標準格式訊息 CAN 2.B (Extended Format) ( 延伸格式 ) - 可以接收 CAN2.A 訊息 - 29 位元訊息識別字 - 位元給 CAN2.A 訊息 +8 位元給 CAN2.B 訊息

管理以及協同應用間連線的終止之通訊控制架構,CAN 不採用 Presentation 演示層 : CAN 不採用 Application 應用層提供使用者存取 OSI 環境及提供分散式資訊服務, 使用者應用程式及 OBD 服務位於此層 CAN Data Frames CAN 2.

6 J939 Main Documents (J939 主要文件 ) SAE J939 - 串列控制及通訊建議實作 SAE J939/ - Physical Layer ( 實體層 ) SAE J939/3 - Off Board Diagnostic Connector SAE J939/2 - Data Link Layer ( 資料連結層 ) SAE J939/3 - Network Layer ( 網路層 ) SAE J939/7 - Vehicle Application Layer ( 車輛應用層 ) SAE J939/73 - Application Layer Diagnostics OBD ( 應用層診斷 -OBD) SAE J939/8 - Network management Protocol ( 網路管理協定 ) Vehicle Network / Engine Management Instruments past futur Engine Sensors Electroni

Vehicle Application Layer ( 車輛應用層 ) SAE J939/73 - Application Layer Diagnostics OBD ( 應用層診斷 -OBD) SAE J939/8 -

7 引擎和驅動系統通訊系統安全防護系統舒適系統監控系統冷暖氣控制器座位調整和位置記憶車速控制器底盤控制器中控裝置

8 過早的科技新的科技 CAN- 數據接 CAN-Bus CAN- 數據傳輸線

9 CAN- 連線方式 CAN-H CAN-L 連接方式指令單元電動窗左電動窗右控制器

10 數據線上的訊號 CAN-H CAN-L CAN-H 和 CAN-L 的訊號電位 CAN-H normal CAN-H Invertiert CAN-L normal CAN-L normal

11 訊號輸入差動 3,75 V CAN-H 2,5 V,25 V CAN-L 2,5 V V CAN- D CAN-H - CAN-L = CAN-Differenzsignal Double-Wire Voltage Levels: High Speed High-Speed definitions according to ISO 3. Volt CAN- 2.. CAN- Tim Recessi Domina Recessi

12 Double-Wire Voltage Levels: Low Speed Low-Speed definitions according to ISO Volt CAN- CAN-.7. Recessi Domina Recessi Tim 電磁波干擾總結 : CAN- 訊號

13 CAN-L 訊號是鏡射相反於 CAN-H 訊號在 Bu s 線路上可以發 CAN-H und CAN-L 的訊號訊號輸入差動 CAN-D und CAN-L 的合併是來自於訊號 CAN-H 電磁波干擾可能造成訊息傳輸重大的損失電磁波干擾可以經過線路繞阻來降低經由訊號輸入差動 CAN-D 可以抗干擾

14 終端電阻 2 2 R II = 6 Ω 總結 : 終端電阻終端電阻可以降低線路上的響應 Echo 和減少因此所產生的雜訊

15 CAN Basics Main features of CANbus Baudrate Mbits/s Bus lenght 4 m Error probability: < 4.7 * -4 International standard (ISO 898) User data/message: - 8 bytes Message cycle time:... ms Data rates Good real-time capabilities Small latency ( fast enough ) indispensable for automotive applications. Data rate dependent on bus length Data rate: Mbit/sec Bus length: 4 meters, Data rate: 25 kbit/sec Bus length: 5 meters, Data rate: 5 kbit/sec Bus length: meters. Typical definitions: Low-speed: 25 kbit/sec up to 25 kbit/sec. High-speed: 5 kbit/sec up to Mbit/sec.

.. ms Data rates Good real-time capabilities Small latency ( fast enough ) indispensable for automotive applications.

16 傳輸速度 S p a n n u n g in V bit =.5 ms X = bit.5 ms X = 66,7 bit ms Breite für 2 bits =.3 ms Zeit in ms X ~ 65 bit s X ~ 65 kbit s 總結 : 傳輸速度舒適 bus 系統工作時是以此傳輸速度 62,5 kbit s 其他的 Bus 系統工作時是以較高的速度介於 25 kbit Mbit s s

17 訊息 CAN-D 訊息訊息訊息控制器訊息拒絕傳送和接收一個訊息操作單元訊息提供電動窗馬達訊息引用訊息檢測訊息檢測訊息接收訊息輸出訊息接收所有的裝置都有可能做訊息的輸出和接收接收 : 所有裝置會保留訊息, 檢測訊息和視需求引用訊息輸出 : 各裝置依次輸出自己的訊息

18 Data Frame: Formats Standard Format (CAN 2.A): -bit Identifier 2 = 248 (in reality only 232) identifiers possible Bus Idle Arbitration Field Control Field Data Field CRC Field Ack End of Field Frame Field Interframe Space Bus Idle recessiv e Bus Idle S O F -bit Identifier R I r T D R E DL C..64 Bit Data 5-bit CRC D A D E C E L K L 7-bit EOF domina nt Extended Format (CAN 2.B): 29-bit Identifier 2 29 = identifiers possible IF S Bus Idle Bus Idle Arbitration field Control Field Data Field CRC Field Ack End of Field Frame Field Inter- Bus frame Idle Space recessiv e domina nt Bus Idle S O F -bit Base Id S I R D R E 8-bit Ext. Id R r r T R DL C..64 Bit Data 5-bit CRC D A D E C E L K L 7-bit EOF IF Bus S Idle Identifier Standard identifier (2.A): - bit identifier 248 logical addresses Standard application in passenger cars Extended identifier (2.B): 29- bit identifier (-bit standard identifier + 8 bit extension) 536 million addresses Standard application in trucks and busses

Bus Idle S O F -bit Identifier R I r T D R E DL C..64 Bit Data 5-bit CRC D A D E C E L K L 7-bit EOF domina nt Extended Format (CAN 2.B): 29-bit Identifier 2 29 = 536.87.

19 Standard data frame (- bit identifier, CAN Spec. 2.A) S O F Identifie r R T R I D E r DLC DATA C R C D e l A C K E O F Identifier = bit ID Name + priority ( = highest priority ) DLC = 4 bit Data lenght DATA = - 8 byte User data Extended data frame (29- bit identifier, CAN Spec. 2.B) S O F Identif. S R R I D E Identififier extended R T R r r DLC DATA C R C D e l A C K E O F Identifier = bit ID Name + priority ( = highest priority ) Ext. ID = 8 bit Extended identifier DLC = 4 bit Data lenght DATA = - 8 byte User data 29- bit identifier, (CAN Spec. 2.B) Priorit y R D P PDU Format PDU Specific Source Address Priority Message priority ( - 7) PDU Format Determins the PGN in the data field (Dest. Addr ) PDU Specific Dest. Addr. or group extension ( ) Source Address Device address ( )

(29- bit identifier, CAN Spec. 2.B) S O F Identif. S R R I D E Identififier extended R T R r r DLC DATA C R C D e l A C K E O F Identifier = bit ID Name + priority ( = highest priority ) Ext.

20 Parameter Group Number (PGN) Identification of a parameter group (PG) in the data field S O F Ident if. S R R I D E Identifi er extend R T R r r DLC DATA C R C D e l A C K E O F R D P PDU Format PDU Specific CALC (FE 6 ) (FEEE 6 ) PDU Format, z.b. 254 PDU Specific, z.b. Example of a Parameter Group (J939/7) (FEEE 6) Name: Engine temperature Transmission rate: s Data lenght: 8 bytes Source Adress: PDU Format: 254 Dec PDU Specific: 238 Dec Priority: 6

65.262 (FEEE 6 ) PDU Format, z.b. 254 PDU Specific, z.b. Example of a Parameter Group (J939/7) 65.

21 Description of data bytes - Engine temperature PG Number (FEEE 6 ) byte byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 byte 8 byte: Engine coolant temperature 2 Fuel temperature 3+4 Engine oil temperature 5+6 Turbo oil temperature 7 Engine intercooler temperature 8 Engine intercooler thermostat opening Data file description of data bytes byte : Engine coolant temperature Data lenght: byte Resolution: C/bit gain, -4 C offset Data range: -4 C to +2 C Type: Measured byte 2: Fuel temperature Data lenght: byte Resolution: C/bit gain, -4 C offset Data range: -4 C to +2 C Type: Measured

22 byte 3+4: Engine oil temperature Data lenght: 2 bytes Resolution:,325 C/bit gain, -273 C offset Data range: -273 C to +735, C Type: Measured byte 5+6: Turbo o il temperature Data lenght: 2 bytes Resolution:,325 C/bit gain, -273 C offset Data range: -273 C to +735, C Type: Measured byte 7: Engine inte rcooler temperature Data lenght: byte Resolution: C/bit gain, -4 C offset Data rang e: -4 C to +2 C Type: Measured byte 8: Engine intercooler thermostat temperature Data lenght: byte Resolution:,4%/bit gain, % offset Data rang e: % to % Type: Measured

23 Message Message Definition Nam e ID [Hex] Repetio n rate Byte Parameter SAE J939/7 Resolutio n Operating Data Range EEC 8 FE EE PGN= s Engine temperature Engine coolant temperature C -4 to +2 C 2 Fuel temperature C -4 to +2 C 3,4 Engine oil temperature C -273 to C 5,6 Turbo oil temperature C -273 to C 7 Engine intercooler temperature C -4 to +2 C 8 Engine intercooler thermostat opening % to % 一個訊息的組合訊息裝置代表號區域數據區域安全檢測區域

24 裝置代表號區域 ( Bit) 訊二進十六進 6 十進制 552 Recessive and dominant bus Hardware representation of recessive and dominant bus levels 5V Bus S E Transceiver S E Transceiver 2 S E Transceiver 3 Wired-AND / Open-Collector circuit

25 Sta withdr Unit recess domin Bu s SO loses Sta Unit 2 recess domin Bu s SO wins arbitration Sta withdr Unit 3 recess domin Bu s SO loses Bus level recess domin J-939 CAN 2.B 29-bit Identifier-extended data frame (J-939 CAN 2.B 29- 位元識別字 - 延伸封包 ) PGN P P P r d F F F F F F F F S S S S S S S S A A A A A A A A PPP = 3 bit message Priority( 訊息優先順序 ) (Highest - 7 Lowest) r = bit Reserved Identifier( 保留識別字 )() d = bit Data Page( 資料頁 ) () FFFFFFFF = 8 bit PDU Format( 協定資料單元格式 )(PF) SSSSSSSS = 8 bit PDU Specific ( 協定資料單元特性 )(PS) AAAAAAAA = 8 bit Source Address of transmitting device( 傳送裝置原始位址 )

26 J-939 Parameter Group Number Messages PGN Name Description PGN Name Description TSC Torque / Speed Control 6525 Engine Configuration 644 ERC Elec. Retarder Control Shutdown 644 EBC Elec. Brake Control Engine Hours 6442 ETC Elec.Trans Control Component Identification 6443 EEC2 Elec. Engine Control # Engine Temperature 6444 EEC Elec. Engine Control # Engine Fluid Level / Pressure 6445 ETC2 Elec. Trans Control Power Take-Off 6527 High Resolution Vehicle Distance Cruise Control / Vehicle Speed Active Diagnostic Trouble Codes Fuel Economy Software ID Ambient Conditions EEC3 Elec. Engine Control # Inlet / Exhaust Conditions Retarder Configuration 6527 Vehicle Electric Power Transmission repetition rate: Engine speed dependent ( 傳輸重複率 : 依引擎轉速而定 ) Data length: ( 資料長度 ) 8 bytes Data page: ( 資料頁 ) PDU Format: ( 協定資料單元格式 )24 PDU Specific ( 協定資料單元規範 )4 Default Priority:( 原始優先權 ) 3 Parameter group number: 6,444 (xf4) ( 參數群組號碼 ) Byte Status EECBit 8-5 Not defined ( 無定義 ) Bit 4- Engine / Retarder Torque Mode ( 引擎 / 阻滯器扭力模式 ) Byte 2 Driver s demand engine percent torque %/bit, -25 to 25%, -25% offset Byte 3 Actual engine percent torque %/bit, -25 to 25%, -25% offset Byte 4,5 Engine speed.25 rpm/bit, to rpm Byte 6-8 Not defined

27 數據區域數據區域數據區域長度 (6 數據 (max. 64 Bit = 數據區域的格式 He 9 C 9 Dua Signa

28 電動窗向上作動 He 9 C 9 電動窗向下作動 He 9 D 9 安全檢測區域監視著輸出和接收作業接收運作輸出者 OK OK OK 接收者接收者 2 接收者 3 至少要有一個裝置接收訊息來運作

29 Bus 電平檢測 Bus 電平檢測裝置檢輸 CA 每一個裝置會測試 Bus 電平裝置輸出一個 Bit 再同時檢測 Bus 電平檢測交換電位原始訊增加一個 Bit 輸出檢測訊 x 6

30 Bit stuffing: Example recess original domin recess stuffed sequen domin stuff Example recess 2 original domin recess stuffed sequen domin stuff Example recess 3 original domin recess stuffed sequen domin stuff stuff Data Frame: Maximum size Maximum frame size (for 8 Data Bytes) without stuff bits with stuff bits Standard Frame CAN 2.A (-bit identifier) bits 3 bits Extended Frame CAN 2.B (29-bit identifier) 3 bits 54 bits

31 在安全檢測區只要有連續五次同樣的 Bit, 就會額外增加一個 Bit 在訊息內做檢測在接收的過濾器中這個額外的 Bit 會被排除固定 Bit 樣本裝置 2 裝置裝置 3 已知的 Bit 樣本會由裝置在輸出端會對已知的固定 Bit 樣本做檢測在接收端會測試這一個已知的 Bit 樣本是否有誤

OSI OSI 15% 20% OSI OSI ISO International Standard Organization 1984 OSI Open-data System Interface Reference Model OSI OSI OSI OSI ISO Prototype Prot

OSI OSI OSI 15% 20% OSI OSI ISO International Standard Organization 1984 OSI Open-data System Interface Reference Model OSI OSI OSI OSI ISO Prototype Protocol OSI OSI OSI OSI OSI O S I 2-1 Application