Problems with Rx/Tx CAN Messages

[digget]

Hi Ben,
First of all, thanks for the great work with your controllers!

We produced two of your motorcontrollers for testing and ran into an issue with the CAN bus.
The interrupt of the CAN receiver doesn't fire and if we try to send messages manually from the controller, it's not visible on the bus.
As it turns out, by measuring with an oscilloscope, the CAN transceiver works just fine and produces a correct signal on the Rx line. Adding a can message to the tx buffer, results in a recessive bus on the Tx line, nothing happens.

Did you ever experience similar behavior with your controllers? We measured all connections from the stm32 to the transceiver and they are connected correctly. We couldn't pinpoint the problem down, and we don't know if our hardware is defective or if it's an issue with the software. Both of our boards have the same behavior.

Maybe you have an idea what's going on.

[yulinwuya]

I have encountered similar problems. Later, it was found that it was caused by CAN and CAN interrupt not being turned on.I thought stm32cubemx would open it for me, but it didn't...

[fabioardiani]

Hi, if I understood well it is the same problem I had, and it was solved by configuring the Rx pin as an internal PULL-UP on the stm32.