Open SAE J1939
SAE J1939 is a protocol for shaping the CAN-bus message in a specific way that suits industrial vehicles such as tractors, machinery, trucks and more.
SAE J1939 is a very easy protocol to use, but there is a lack of information about SAE J1939, due to the cost of the protocol document, available how to shape a CAN-bus message according to SAE J1939 protocol standard. So therefore I’m writing a SAE J1939 protocol available for free to use on any embedded systems such as STM32, Arduino, AVR, PIC etc or PC.
To learn to build on this project, you need first to understand SAE J1939. I have written this project in C language because C is an industry standard. The C language dialect I have chosen is C99 and I don't use dynamical memory allocation in this library. So it will work with MISRA C standard.
With this library, you can communicate with valves, engines, actuators, machinery, hardware and all other things that are suitable for heavy industrial mobile applications. I have build up a basic structure of the project and I hope that other users will send pull request of their C code for extra functionality to SAE J1939 standard because SAE J1939 is a huge standard.
Getting started
The first thing you need to know is to read the document Open SAE J1939.pdf inside the Documentation folder. Learn the structure of the project, else you won't be able to understand SAE J1939. After you have got a basic understanding of the project, you are able to build on it. Keep it simple and follow the SAE J1939 standard!
After you have understand the structure of the project, then select processor choice in Processor_choice.h file. Here you can select for example STM32, Arduino, PIC, AVR etc. or if you want to run it on PC first, then select PROCESSOR_CHOICE 0 and run some examples. That's the debugging mode for internal CAN feedback.
How to use the project
- Step 1: Download this repository
- Step 2: Go to
Processor_choice.hand select your processor, if it's not avaiable, please write code for it and send me a pull request - Step 3: Copy over the
Srcfolder to your project folder inside your IDE. RenameSrcto for exampleOpen SAE J1939. That's a good name. - Step 4: Past the header files inside your application code. This is just an example.
#include <stdlib.h>
#include <stdio.h>
#include "ISO_11783/ISO_11783-7_Application_Layer/Application_Layer.h"
#include "Open_SAE_J1939/Open_SAE_J1939.h"
#include "SAE_J1939/SAE_J1939-71_Application_Layer/Application_Layer.h"
#include "SAE_J1939/SAE_J1939-73_Diagnostics_Layer/Diagnostics_Layer.h"
#include "SAE_J1939/SAE_J1939-81_Network_Management_Layer/Network_Management_Layer.h"
- Step 5: Create the
J1939 j1939 = {0};inside your application code. You can see inside the examples how I have done - Step 6: Set the other ECU addresses to broadcast address
0xFF
/* Important to sent all non-address to 0xFF - Else we cannot use ECU address 0x0 because this library remembers the ECU addresses. */
for(uint8_t i = 0; i < 255; i++)
j1939.other_ECU_address[i] = 0xFF; /* 0xFF is not an ECU address, only a broadcast address according to SAE J1939 */
- Step 7: Set your ECU address between
0x0to0xFD. I select0x80
j1939.this_ECU_address = 0x80;
- Step 8: Create
NAME. It's aSAE J1939standard for sending out theNAMEof the ECU at the start up. Don't forget to look inSAE J1939 Enumsfolder for more predefined fields forNAME
/* Set NAME for ECU 1 */
j1939.this_name.identity_number = 100; /* From 0 to 2097151 */
j1939.this_name.manufacturer_code = 300; /* From 0 to 2047 */
j1939.this_name.function_instance = 10; /* From 0 to 31 */
j1939.this_name.ECU_instance = 2; /* From 0 to 7 */
j1939.this_name.function = FUNCTION_VDC_MODULE; /* From 0 to 255 */
j1939.this_name.vehicle_system = 100; /* From 0 to 127 */
j1939.this_name.arbitrary_address_capable = 0; /* From 0 to 1 */
j1939.this_name.industry_group = INDUSTRY_GROUP_CONSTRUCTION; /* From 0 to 7 */
j1939.this_name.vehicle_system_instance = 10; /* From 0 to 15 */
Step 9: Broadcast the NAME
SAE_J1939_Response_Request_Address_Claimed(&j1939); /* This function send out the NAME to all ECU */
- Step 10: Implement your reading function inside a while loop
while(1) {
/* Read incoming messages */
Open_SAE_J1939_Listen_For_Messages(&j1939);
/* Your application code here */
....
....
....
}
Now you can use the Open SAE J1939 library
The structure of the project
SAE J1939 functionality
- SAE J1939:21 Transport Layer
- Acknowledgement
- Request
- Transport Protocol Connection Management
- Transport Protocol Data Transfer
- SAE J1939:71 Application Layer
- Request Component Identification
- Request ECU Identification
- Request Software Identification
- SAE J1939:73 Diagnostics Layer
- DM1
- DM2
- DM3
- DM14
- DM15
- DM16
- SAE J1939:81 Network Management Layer
- Address Claimed
- Commanded Address
- Address Not Claimed
- Delete Address
Extra functionality
- ISO 11783 Tractors And Machinery For Agriculture And Forestry
- ISO 11783-7 Implement Messages Application Layer
- Auxiliary Valve Command
- Auxiliary Valve Estimated Flow
- Auxiliary Valve Measured Position
- General Purpose Valve Command
- General Purpose Valve Estimated Flow
- ISO 11783-7 Implement Messages Application Layer
Questions and answers
- Q: Can this library be used with
C++?- A: Yes it can be used with
C++
- A: Yes it can be used with
- Q: I want to build on this library, what should I do?
- A: First you need to know
C99and bitwise operations. Then you need to understand theSAE J1939:21 Transport Layerstructure. Don't forget to update the PDF with your new functionality.
- A: First you need to know
- Q: Can I use this on my Arduino?
- A: Yes, this
Ccode is 100% pureCcode and only usingCstandard library and also the code does not take account of what hardware you are using.
- A: Yes, this
- Q: Do I need to install the library for to use the library?
- A: No, just copy over the
.cand.hfiles to your project and compile. I have used this with QT framework.
- A: No, just copy over the
- Q: This project is quite old now and not so much updates, is it still worth to use it?
- A: Yes, this library only updates when I or other includes more functionality from SAE J1939. The reason why I wrote this in
C99is because it's an industry standard and will you will always be able to compile this library and use it.
- A: Yes, this library only updates when I or other includes more functionality from SAE J1939. The reason why I wrote this in
- Q: What is your plan with the library?
- A: To make SAE J1939 available for everybody
- Q: I don't have CAN-bus, but can I use this library anyway with UART, USB, WiFi etc?
- A: Yes. This is only a way to shape a massage in a specific way.
- Q: Can I send data with this library, even if I don't have CAN-bus?
- A: Yes. There are something called DM14 transmit request, DM15 status response and DM16 binary transfer. Use that if you want to transfer data in an industrial way.
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