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CAN – Message Conflict Detection

Question asked by Mark Edwards on May 13, 2015
Latest reply on May 20, 2015 by Mark Edwards
I am building a CAN Analyser using the STM32F429.
At present I am only using one of the CAN channels and I have I found that if there is
a collision during transmission when the NART bit is set then the MPU continues as if
no problem occurred despite the message not getting sent. Clearing the NART bit, the
message is sent but I still don’t see any indication that a problem occurred.
So my question is, is there something I am missing?

At the moment the only way around the problem that I can see is to connect the CAN1&2
channels together and transmit on one channel and monitor the received data on the
second to ensure that that messages I send are actually sent.
I have designed in the capability to monitor the CAN TX/RX lines using EXTI so could
examine the packet structure to look for collisions but I feel that transmission
errors should be visible using the CAN registers but can’t see where.
Schematic Attached.

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