Teensy 4.1: How to check CAN is defective

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How to use analyser?

Hello Paul:

My CanUSB arrived and I hooked it up as you showed and downloaded the software.

Can you please show me the testing steps. I attached what I tried but there is no response.

Thanks in advance.
 

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Hi Jimmie, you need to click the "Set and Start" button to start receiving CAN frames:

CANanalyzer.png

Paul
 
Thank you Paul.

Here are the exact steps I did:

1) Select Com Port.
2) Select "Standard frame" for Type
3) Select CAN bps 500kbps
4) Opened Com Port
5) Clicked on Set and Start
6) Checked AutoAnswer

....

What is the next step?
 

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See my message #23. There you can see the CAN analyzer screen with the settings I used.
For the CAN analyzer to "Auto-answer" you have to tell the anayzer what exactly to return when a certain CAN message comes in.

CANanalyzer.png

Paul
 
Some more info with respect to the screen dump from message #23:
- The Teensy runs your program. It sends out frame ID 740, data 06 04 00 00 00 00 00 00. The analyzer shows this in the bottom window as "Receive".
- The analyzer responds with frame ID 751, data 00 01 02 03 04 05 06 07. The analyzer shows this in the bottom window as "Send".

If you don't see the reception of frame ID 740, your CAN transmit circuitry is broken [and your analyzer will not return anything obviously].

Paul
 
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I am not sure what I am doing incorrectly.

I connected the circuit as you showed in message #23. I am using the waveshare module because I know it works.

The CANUSB module's green light flashes twice indicating a receive.

I set up the software with the steps numbered as shown.

Am I missing anything else?

Thank you.
 

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It looks like you set everything correctly in the analyzer.
However the bottom windows does not show the reception of any frame.
That green LED flash may not necessarily mean that a correct frame has been received - the LED may just indicate some electrical CAN bus activity.
Did you try swapping the CANL & CANH lines?

Paul
 
When I swapped the CANL and CANH lines and restarted, the green light stopped flashing. When I put them back as before, the green light flashes.

I am sure CANL and CANH are wired correctly ....

Yes, also Teesny GND is connected to analyzer GND.
 
Hmm, the plot thickens...
When the CAN bus is idle [Teensy and analyzer not sending data] I measure 2.5Vdc between GND & CANL and between GND & CANH on the 3-pin analyzer connector.
Do you see the same?

Paul
 
That seems OK.
I'm out of ideas for now.
Can you perhaps send a photo of your setup? Are you still using your custom board or did you perhaps make a basic breadboard setup like I did?

Going offline now and get some sleep. Back again tomorrow.

Paul
 
Thank you for your help. I will send you a picture (I am not using the custom board).

When you have a chance, please send me your analyzer .ini files.

Thanks again and good night.
 
Thank you Paul. I found the problem.

It turns out it is related (most likely) to driver behavior with Windows 7. I first did a loop test on the analyzer, and it did not work so I reset the analyzer by shorting the open jumper but the loop test still did not work.

So I moved to a Win10 machine and reset the analyzer. After I did that, the loop test worked.

I then proceeded to test the CAN modules. Sure enough, the Waveshare worked (see attached). None of the three other modules worked despite being from two different vendors! So there must be a large number of bogus TI chips floating around!!

Thanks again for your time and help. I appreciate it.

BTW, I found all the software here:

http://github.com/SeeedDocument/USB-CAN-Analyzer
 

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Great! Happy to hear that it is finally working.
Now on to your custom board...
Noticing your experience with the cheapo boards, I'll stick with Waveshare boards for mission-critical applications as well.

Paul
 
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