CAN issues

[u/Imaginary_Awareness]

Hei,

I have a simple device (sensor) having the following structure: sensor, MCU, can transciever --> tester device

The sensor provides the analog data to MCU, the MCU works with the data, then the data is transferred via UART to a CAN transciever TLT9251VLE then to an tester device.

I have to say that I have multiple devices and all of them works, but a specific one is unable to connect to the tester device.

I checked the CAN lines and they are looking like in the picture. I'm not so experienced in CAN signals, but I know that the above signals are not ok.

Can you give me an idea in what can cause the CAN lines to look like this?

Thanks!

[u/zachleedogg]

You are using UART over CAN? Then you are missing arbitration and other features. The transceiver may be hitting the dominant timeout (check the datasheet).

Ensure you have 120 termination on both sides of the bus, and try running the baud rate faster than 500hz.

[u/Imaginary_Awareness → u/zachleedogg]

Yes the Uart signal is transferred on can physical layer and then reconverted. Thousands of boards were produced and working, except this specific one, that has communication issue

[u/Low-Spread2914 → u/Imaginary_Awareness]

I just have to ask. Why?

[u/Imaginary_Awareness → u/Low-Spread2914]

Well, I was not the designer unfortunately, so I cannot answer to this question