Hi
I’m working with CAN on a TM4C123, using the example in the Tiva peripheral library.
I've successfully uploaded the example simple_rx.c to my board. Using a 'scope I can see messages arriving at the board (though I don’t know for certain yet they’re correctly configured), whereupon the interrupt handler CANIntHandler() gets called.
In the example code, CANIntHandler() determines the cause of interrupts via
ui32Status = CANIntStatus(CAN0_BASE, CAN_INT_STS_CAUSE);
In my case, the returned value is
ui32Status == CAN_INT_INTID_STATUS
Simple_rx.c implies this indicates some sort of error occurred (since otherwise the code says “else if ui32Status ==1”)
The example goes on to say that you can diagnose the error by calling
ui32Status = CANStatusGet(CAN0_BASE, CAN_STS_CONTROL);
and examining the field of error bits returned
When I do this however, the return value I'm seeing is
ui32Status = CAN_STATUS_RXOK (i.e. "a message was received successfully”)
(I’m determining this simply by adding some lines to compare ui32Status against all allowed values -
If (ui32Status & CAN_STATUS_BUS_OFF) UARTPrintf(“BUS OFF”);
If (ui32Status & CAN_STATUS _EWARN) UARTPrintf (“EWARN”);
//Etc. )
I’m struggling to interpret this: On the one hand the call to CANIntStatus() didn’t return ‘1’, implying a problem…but the 'problem' is “RXOK - a message was received successfully”.
What am I missing?
And/or, if there is a problem with my CAN messages, is there a way to get some further diagnostic information from the API?
Many thanks for any help
