PEAK-System Forum

Dear Readers,
I use a Waveshare Open407V-D board with a STM32F4-Discovery.
I connected the two CAN-Ports with transceivers and cables and implemented
an endless loop CAN1 to CAN2 and back again. It works endlessly without any problems.

Now I place the software with the STM32F4-Discovery on a Mikroelektronika eval board with
CAN-Transceiver and try to connect it to PCAN-USB.

Whatever I do: I always get a BUSHEAVY message.
I never received an interrupt on the evalboard nor a byte in the PCAN-View.
The BTR registers are the same on evalboard and in the PCAN-VIEW
I implemented two SCE handlers -> they are never called,
but I am not sure if they are working at all,
because I do not know how to enforce an error on the bus.

The jack to the PCAN_VIEW is selfmade, but I looked 1000 times in the Pinlayout -> it is correct.

What is that and how can I proceed?

Regards
Espen

Checklist:
- Cable should be terminated - in Sum 60 Ohm between CAN-H and CAN-L (could be measured when system is unpowered)
- Try to connect only CAN-H to CAN-H and CAN-L to CAN-L only - no GND
- Check thi Bitrate - exactly - this is veryx importend - use aour Bitrate calculation tool to find teh settings that you use with your CAN Board (Sample Point etc.) --> LINK
- If you own a scope. pleas esend us some pictures of the CAN-H to GND and CAN-L to GND, also a differential measureing betwenn CAN-H and CAN-L while CAN Traffic should be on the BUS
- measure your Transceiver Voltage to be sure the Transceiver is not defect --> LINK

Thank you for oyur message!

>- Cable should be terminated - in Sum 60 Ohm between CAN-H and CAN-L (could be measured when system is unpowered)
There is a terminator on the board and I must rely on its proper working.

>- Try to connect only CAN-H to CAN-H and CAN-L to CAN-L only - no GND
Done no effect.

>- Check thi Bitrate - exactly - this is veryx importend - use aour Bitrate calculation tool to find teh settings that you use with your CAN Board >(Sample Point etc.) --> LINK
This is seemingly an issue ( it is probably sitting in front of the computer )
That can only mean that I ( 1 Mbit/s are in the end required ) I have to adapt my settings to yours.
I can not adust yours clock from 8Mhz to 80Mhz(my clock) in yours 1 Mbit/s settings.
When I do that than you have 8 Tqs and I have 10.
That can not work in my understanding.
What have I overseen?

>- If you own a scope. pleas esend us some pictures of the CAN-H to GND and CAN-L to GND, also a differential measureing betwenn CAN-H and >CAN-L while CAN Traffic should be on the BUS
I don't own a scope.

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There is a terminator on the board and I must rely on its proper working.

Simply measure it if it is OK - do not rely on others work.

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This is seemingly an issue ( it is probably sitting in front of the computer ) That can only mean that I ( 1 Mbit/s are in the end required ) I have to adapt my settings to yours.
I can not adust yours clock from 8Mhz to 80Mhz(my clock) in yours 1 Mbit/s settings. When I do that than you have 8 Tqs and I have 10.
That can not work in my understanding. What have I overseen?

Try to use lower Bitrates first and be sure you have setup the right settings (Sample point etc.)
And no - you could not change the Frequenzy of the older PCAN-CAN USB - but this have nothing to do that you could not setup a correct timing.
Please use - as recommended - the Bitrate Tool to calculate the BTR0/BTR1 that you need to get the CAN USB work with the settings of your board

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I don't own a scope.

Thats bad - but then you need to solve it without a scope.

Meanwhile I have solved the problem by terminating the cable.
I was not believing in this, but it worked.
Thank you for your support!

Thanks for the feedback!
See our first answer - Checklist -

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