http://www.auto-diagnostics.info/j1850

j1850

The SAE J1850 bus bus is used for diagnostics and data sharing applications in vehicles. The J1850 bus takes two forms:

  • 41.6Kbps Pulse Width Modulated (PWM) two wire differential approach (Ford vehicles)
  • 10.4Kbps Variable Pulse Width (VPW) single wire approach (GM vehicles)

The single wire approach may have a bus length up to 35 meters (with 32 nodes). Developed in 1994, J1850 may be phased out for new designs. The J1850 Interface is a class B protocol.

A high resides between 4.25 volts and 20 volts, a low is any thing below 3.5 volts. High and low values are sent as bit symbols (not single bits). Symbols times are 64uS and 128uS for the single wire approach. The bus uses a weak pull-down, the driver needs to pull the bus high, high signals are considered dominant. A passive logic 1 is sent as a 128uS low level, an active logic 1 is sent as a 64uS high. A passive logic 0 is sent as a 64uS low level, an active logic 0 is sent as a 128uS high. The J1850 protocol uses CSMA/CR arbitration.

J1850 Frame structure

The frame consists of a Start Of Frame [SOF], which is high for 200uS.

The Header byte follows the SOF and is one byte long.

The data follows the header byte.

The one byte CRC [Cyclical Redundancy Check] follows the data field.

After the CRC an End Of Data [EOD] symbol is sent.

The EOD is sent as a 200uS low pulse.

J1850 Transmission Signal Format

In many cases the J1850 interface bits will be found on an OBDII connector inside a passenger car.

OBDII [On-Board Diagnostics II] defines a communications protocol and a standard connector to acquire data from passenger cars.

However because of the age of the J1850 bus standard, it may not reside on newer late model vehicles which use CAN-BUS.

Real J1850 PWM signal as measured in our lab

http://www.emotive.de/en/de/doc/car-diagnostic-systems/bus-systems/sae-j1850

http://www.shieldedpair.net/BAE5030/Lectures/J1850%20Introduction.pdf

VPW Waveform

PWM Waveform

http://www.obddiag.net/allpro.html

http://www.obddiag.net/images/allprousb.pdf

OBD-II Protocol -- SAE J1850 VPW PWM的更多相关文章

  1. SAE J1850 VPW PWM, SAE J2411 SWC, ISO 11898 CAN, SAE J1708, Chrysler CCD 接口芯片电路

    SAE J1850 VPW 接口芯片电路 SAE J1850 PWM 接口芯片电路 SAE J2411 SWC 接口芯片电路 ISO 11898 CAN 接口芯片电路 CANH 和CANL 上的电容 ...

  2. OBD Experts OBD II Software OBD II Protocol Stack

    http://www.obdexperts.co.uk/stack.html OBD II Software OBD Experts can provide you with ready to use ...

  3. SAE J1850 VPW Implement

    ---恢复内容开始--- OBDII Interface Project When I can ever find enough time away from schoolwork, I try to ...

  4. BR16F84 OBD II Interface Chip For PWM, VPW, and ISO 9141-2 Vehicles

    http://faq.ford77.ru/pdf/eec/DataSheet.pdf FEATURES:Operating Voltage 5.0 VOperating Current 5 Ma. T ...

  5. SAE/ISO standards for Automotive

    On-Board Diagnostics J1962 Diagnostic Connector Equivalent to ISO/DIS 15031-3: December 14, 2001J201 ...

  6. STN1110 Multiprotocol OBD to UART Interpreter

    http://www.obdsol.com/stn1110/ Safe, secure bootloader. Reflash the firmware in the field, even over ...

  7. STN1170 Multiprotocol OBD to UART Interpreter

    http://www.obdsol.com/stn1170/ STN1170 supports the following protocols: all legislated OBD II proto ...

  8. SAE J2534 Pass-Thru API

    Connects to the OBDII J1962 DLC and supports the following protocols. 1 CAN2 Single Wire2 J1850PWM+ ...

  9. On-board diagnostics connector SAE J1962

    http://en.wikipedia.org/wiki/On-board_diagnostics#Standard_interfaces OBD-II diagnostic connector Th ...

随机推荐

  1. 获取SQL Server的版本信息

    微软 SQL Server 版本号 产品名称 发行日期 主版本号 正式版 SP1 SP2 SP3 SP4 SQL Server 2016 2016.06.01 13.00.1601.5 13.00.1 ...

  2. java基础32 List集合下的ArrayList集合

    单例集合体系: ---------| collection  单例集合的根接口--------------| List  如果实现了list接口的集合类,具备的特点:有序,可重复       注:集合 ...

  3. SonarQube的安装、配置与使用(windows)

    onarQube是管理代码质量一个开放平台,可以快速的定位代码中潜在的或者明显的错误,下面将会介绍一下这个工具的安装.配置以及使用. 准备工作: 1.jdk(不再介绍) 2.sonarqube:htt ...

  4. 如何在k8s集群里快速运行一个镜像?

    在docker里,快速run一个镜像,很简单的. k8s的世界,与之类似. 但要注意一下,如果镜像本身没有提供command命令,这个容器由于前台输出完成,很快就退出了. 所以,遇到这种镜像,就最好自 ...

  5. 一些你可能需要的okhttp实现

    https://blog.csdn.net/qq_17766199/article/details/53186874 今天分享一些我在项目中使用到的okhttp实现,由简至难.(以下内容均在okhtt ...

  6. git clone push需要root权限解决方法

    重新装了Linux发现使用git命令必须要sudo,否则会提示权限不够. 解决办法:在ssh生成id_rsa.pub密钥时实际上有两个,根目录的家里.ssh文件夹里有一个,用户家里.sh文件夹里有一个 ...

  7. react篇章-事件处理

    <!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <title&g ...

  8. ASL测试 课题测试博客

    已知线性表具有元素{5,13,19,21,37,56,64,75,80,88,92},如果使用折半查找法,ASL是多少? 知识点1: 折半查找法:折半查找,又称作二分查找.这个查找的算法的特点,要求数 ...

  9. Java 中的三大特性

    我们都知道 Java 中有三大特性,那就是继承 ,封装和多态 .那我今天我就来说说这几个特性 . 老样子 ,先问问自己为什么会存在这些特性 .首先说封装 ,封装就是使用权限修饰符来实现对属性的隐藏 , ...

  10. JAVAEE——宜立方商城10:使用freemarker实现网页静态化、ActiveMq同步生成静态网页、Sso单点登录系统分析

    1. 学习计划 1.使用freemarker实现网页静态化 2.ActiveMq同步生成静态网页 2. 网页静态化 可以使用Freemarker实现网页静态化. 2.1. 什么是freemarker ...