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View canbus data


Smwoodward

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I've been trying to get the cruise control input into my ecu to configure it.  I have everything hooked up to the canbus and I can see the data from my steering wheel and from the ecu on a can sniffer, but it doesn't look like the canbus data is getting into the ecu.  Is there a way that I can view the raw canbus data that the ecu is seeing?

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I've got a canchecked CFE18 module in the steering wheel, and want to control the cruise control to the ecu over canbus.  Attached is a picture of the raw canbus.  I see where 3e8-3eb is the ecu data, 700-702 is the CFE18 and when I control the cruise input, I see the first 2 bytes change.  However I can't seem to get the ecut to see and input those controls.  I've also tried doing a digital input to see if one of the can DI's will change, but it doesn't seem like it's responding either.  

I'll upload the tune on the next comment.

IMG_4675.HEIC

forums.pclx

I think I figured it out.  I didn't realize that link ecu used the decimal for the ID and not the HEX value.

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Yeah I've got that working, and thanks for your time  on it.

 

Another question I have is the difference between Generic Dash and Generic Dash 2.  I see the information in the help about the output information in these two, but looking at the raw canbus, I don't see where all of the data for Generic Dash is being addressed to.  I can go through and create custom streams, but the Generic Dash has most of that information already in it, and would use that instead of I could.

 

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Generic dash is what is referred to as a compound message - or sometimes called a multiplexed or row counter.  So with this technique you send multiple frames all with the same ID, typically we use ID 1000 or 0x3E8.  One of the bytes in each frame is used as a further ID so that the receiving device knows what data is in each frame.  This further identifier is called the Compound ID/Frame ID/Multiplexor or row counter.  Example from Generic dash below, Byte 0 is the frame ID.  So if the receiving device receives a frame with a value of 2 in byte 0, then it knows this frame has Inj DC, Inj PW & ECT in the 6 data bytes.  

M4OIltP.png

 

Generic Dash 2 is what is referred to as a sequential message.  With this technique even though you still only set one ID in the software, the ECU will send out only one frame on that base ID, then each further frame is sent with an ID that increments by 1. 

In generic Dash 2 there are 4 frames of data, so the first frame gets sent on ID 1000, the second frame on 1001, 3rd on ID 1002 etc.   

 

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