High-performance SAE J software based protocol stack. Complete J source code is provided. 15 Nov Get on the Bus: J and J Vehicle Bus Standards on established protocols that vary based on vehicle manufacturer, vehicle model. 14 Nov J defines the physical layer, which are the hardware (wiring) and basic protocol that is needed for J and J to transmit messages.

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J Physical Layer J uses a twisted pair of wires, with a minimum wire size of gauge. I think that not many eng.

Omnitracs makes no representations, warranties, or other commitments whatsoever about any non-Omnitracs sites or third-party resources that may be referenced, accessible from, or linked to this site. J Inter-character Bit Time For bytes to be considered as part of a message, the time between bytes is not allowed to exceed 2 bit times.

I did not get any usefull response on my repeater question. There are numerous CAN forums on the web. Problems with Programming Oscillator in XC16 Is it possible to stretch a pulse signal using only microcontroller?

Opinions expressed in the content posted here are the personal opinions of the original authors, and do not necessarily reflect those of Omnitracs, LLC or its subsidiaries “Omnitracs”. Also, the message length of J is variable up to 21 bytes for standard messages. SAE J is a standard used for serial communications between ECUs on a heavy duty vehicle and also between a computer and the vehicle.

More correctly, request data. The maximum allowed bus access time is 50 microseconds. A logical 1 is when wire A is more than 0. The bus is considered idle if there is no activity i.


It uses 8, N, 1 byte framing and has a network speed of bits per second bps. Since this post were made in January we also advaced great steps in CAN development and I must admit that Microchip Switzerland got on Board with us and supported us with Technical know how and advice. It is just strange that not one of the microchip application Engineers get involved in this topic. And that’s just the beginning.

J and J Vehicle Bus Standards | Omnitracs

By using this site, you agree to the Terms of Use and Privacy Policy. By most heavy duty truck and engine manufacturers had adopted at least a partial implementation of J J uses a twisted pair of wires, with a protockl wire size of gauge. The last byte of every message is the two’s complement of the MID and data contained in the message.

The messages are prioritized and one can both send and recieve. Starting init included a specific diagnostic connector to be used on all heavy duty vehicles. It also added the option for a second CAN connection for proprietary data networks. It defines the physical layer and data link layer. J Bus Termination J networks do not use bus termination. The basic problem is that the CAN specification defines certain requirements around the identifier, or the first part of the message.

The reason for this is passive mode allows for non-destructive bus arbitration. The only indication of when the message is over is when the transmission stops. From Wikipedia, the free encyclopedia. The protocl is maintained by SAE International.


j1708 and CAN

It is being replaced by J When the voltage difference is less than 0. If the engine is not running and the vehicle is not moving, messages longer than 21 bytes may be transmitted.

I don’t blame microchip for not responding to the vast majority of these postings. The resessive state is high, and dominante is low. J is mainly used on heavy-duty and commercial vehicles. I also post at: J Priority In J, each message is defined a priority. This page was last edited on 29 Aprilat Collisions are avoided by monitoring the bus while transmitting the MID to ensure that another node has not simultaneously transmitted a MID with a higher priority.

Do you know if your trucks are J or J? A logic 0 is when B is 0. J and J Vehicle Bus Standards. While market demand for vehicle electronics are driving innovation and complexity, the networked vehicle originated from government requirements to control and regulate vehicle emissions and reduce air pollution. Automotive standards Technology stubs.

J1587 / J1708 Network Operation and Testing

J communicates diagnostic information, while J communicates control data. If so, if the j protocol is on the rs physical layer, can the CAN be interface to the rs so it can interpret the j protocol??? The maximum length, from the MID to the protool, is 21 bytes. Retrieved from ” https: