SAE J1939 to Bluetooth Gateway Module

The J1939.BT gateway is a high-performance, low-latency, wireless vehicle network adapter for SAE J1939 applications. It allows any host device with a Bluetooth COM port to monitor SAE J1939 data traffic and communicate with the SAE J1939 vehicle network.

The gateway supports the complete SAE protocol per the Network Management (Address Claiming) and Transport Protocol (TP) documents numbered J1939/81 and J1939/21, respectively. Additionally, it comes with a programming interface compatible with Windows and Linux/Ubuntu applications. The interface includes complete source code in C/C++/C# to enable faster and more efficient development.

The strength of the gateway lies in its ability to store the entire SAE J1939 protocol, including all timing requirements, on-chip. This means that the main system is relieved of this burden. The board uses a wireless Bluetooth COM port to communicate with the main system, and all data transfer is handled through a standard COM port access. The communication protocol between the board and the main system is well documented, which allows it to be ported to any computer system with a Bluetooth connection. Working source code libraries are available for Windows (C# under Visual Studio 2102/2013), Linux and its derivatives (C++ using Code::Blocks), and Raspberry Pi (C using the standard GCC compiler).

The J1939.BT gateway has many features that enable the simulation of an SAE J1939 ECU (Electronic Control Unit) using embedded solutions like Raspberry Pi, BeagleBone, Arduino, Teensy, and others. It can also be used with PCs running Windows, Linux (including Ubuntu, Fedora, etc.), Android, or iOS.

External BT Antenna

We chose an external antenna over a PCB type to ensure the best transmission quality. Research indicates that when a Bluetooth antenna is placed inside or next to a plastic enclosure, its RF signal is impeded by as much as 37.5%. As a result, the broadcast signal can shift from the official Bluetooth frequency range, between 2.4 and 2.4835GHz, to 2.159GHz.

Ref: Plastic enclosures may impede Bluetooth signals – EE Times…

Windows Software

The communication protocol between the gateway and the host system (PC, Embedded System, Android System, etc.) is well documented, and we provide C source code to read and write CAN data frames.

In addition, the gateway is supported by our JCOM1939 Monitor, an SAE J1939 Monitoring, Analyzer, and ECU Simulation software under Windows.

The jCOM1939 Monitor Software is the perfect tool to monitor, analyze, and simulate SAE J1939 data traffic.

The system combines powerful monitoring software with our jCOM.J1939.BT, which functions as an SAE J1939 to Bluetooth gateway.

A comprehensive, easy-to-use, and easy-to-understand Windows software displays SAE J1939 data traffic. It allows one to scan the network, simulate an ECU (including full node address negotiation features), and respond to data request messages.

Features

CAN Bus Interface – Fully ISO-11898 Compliant
Onboard Interface for On-Site Firmware Update
Bluetooth port with external antenna
SAE J1939 Protocol Stack
Extended Temperature Range of -40C to +85C
Input Power Range of 7 VDC to 36 VDC
Flame Retardant ABS Enclosure 3.29 x 2.42 x 1.00 in / 83.57 x 61.47 x 25.40 mm
Environmentally friendly, RoHS compliant

Specifications

CAN Interface
- CAN Controller integrated into a microcontroller
- Fully ISO 11898-compliant
- Supports CAN 2.0A And CAN 2.0B
- Bit rate 250/500 kBaud
Bluetooth Connection
- Fully certified Bluetooth version 2.1
- Backwards compatible with Bluetooth versions 2.0, 1.2, and 1.1
- Low power: 26 µA sleep, 3 mA connected, 30 mA transmit
- Bluetooth SIG certified
- Certifications: FCC, IC, CE
SAE J1939 Protocol Stack
- Fully compliant to SAE J1939/21, SAE J1939/81 and SAE J1939/16
- Sending and receiving of messages (PGNs)
- Message filtering
- Request message processing
- BAM and CM transport protocol (TP) processing
- Static and arbitrary address claim

CAN Port

The CAN port has a slide switch to connect/disconnect an onboard 120Ω (0.5W) termination resistor.

J1939 Gateway - CAN Port DB9 Pin Assignment

CAN Bus Termination Resistor

The CAN Standard requires a termination resistor to be installed at both ends of the network, assuming that there are only two ends, which can be challenging to determine in complex network structures. If you’re connecting to an established network, you likely won’t need termination. However, when conducting bench tests, such as connecting to a single test instrument, it’s essential to ensure that both devices, including the BT gateway, are properly terminated.

The BT gateway comes with a 120 Ohm termination resistor activated by default. To deactivate the resistor, open the enclosure, locate the pin jumper as indicated in the image below, and remove the jumper.

J1939 Bluetooth Gateway - Termination Resistor Jumper

Connecting Bluetooth to a Windows PC

How to connect and pair a Bluetooth device with Windows 10…

Connecting Bluetooth to an Android Device

Android Basics: How to connect a Bluetooth Device…

Note:
Some of the information below refers to our previous gateway version. However, the functionality as described is the same. We are working on updating the information.

Documentation

Development Resources

More Resources

A Comprehensible Guide to J1939 is the first work on J1939 besides the SAE J1939 standards collection. It provides profound information on the J1939 message format and network management combined with a high level of readability.

The information in this book is based on two documents of the SAE J1939 Standards Collection:

J1939/21 – Data Link Layer
J1939/81 – Network Management

This book attempts to create an enjoyable and readable J1939 reference for everybody. The information provided in this book is, besides the SAE J1939 Standards Collection, based on publicly available information such as, but not limited to, websites and printed literature, as well as contributions by engineers familiar with Controller Area Network and the J1939 protocol. The information in this book, while based on the J1939 standard, is not a reproduction of any copyrighted SAE document. More Information…