iX Talk

How to send information via J1939?
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Author:  iva [ Thu May 30, 2013 12:34 pm ]
Post subject:  Re: How to send information via J1939?

Thanks a lot! I'll try to work it out.

Author:  iva [ Mon Jun 03, 2013 4:24 am ]
Post subject:  Re: How to send information via J1939?

As i understand, we have only int32-type for tags on transmission.
Is it possible to form 8-bytes message at once. In other words: how to prevent sending a message which is not finished?

Author:  mark.monroe [ Mon Jun 03, 2013 8:56 am ]
Post subject:  Re: How to send information via J1939?

You need to update the tag value with the complete value you want to send. There is no way to partially update a tag's value, then send out the data when you are done.

In the FreeCAN Excel spreadsheet I always thought that you could limit the data you wanted to send to a single bit up 4 bytes, and any combination in between. Obviously only values that can be contained in the CAN memory register that you have specified would work.

Author:  fabiop [ Thu May 05, 2016 6:39 am ]
Post subject:  Re: How to send information via J1939?

with CAN bus sometimes it is really necessary to control *when* a telegram is sent. For example, a telegram contains four tags (A, B, C, D), and the value of those tags shall be aligned.
Let's say initially A=0, B=0, C=0, D=0.
I want to send a telegram with A=1, B=2, C=3, D=4.
So I write a script:

A = 1;
B = 2;
C = 3;
D = 4;

The problem is: as soon as the first instruction is executed, the CiX module sends a telegram with A=1, B=0, C=0, D=0, which is wrong. Is it possible to send a single telegram at a given time? As the original writer of this post alredy mentioned, document "First steps with CiX-CAN FreeCAN.pdf" at page 35 explains something about HRA, HRB but the information is not complete.

Please explain how to use HRA, HRB to send a telegram by direct command

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