Unhandled Interrupt vector 0x9f (159)

[fenz]

Hi,

I'm using an MCF52259 and getting the following error being printed out by MQX.

*** UNHANDLED INTERRUPT ***
Vector #: 636  0x27c
Offset  : 159  0x9f
Task Id: 0x10005 Td_ptr 0x1000bc80 Stack Frame: 0x100006f8
Interrupt_nesting level: 2   PC: 0x000006ea   SR: 0x2204

Then a crash.

Looking at the MCF52259 (16-15) manual the in use vectors stop at 153 (BOFF_INT)

So what's 159?

I would install a handler if I could find out what the interrupt was for.

BTW I am using the FlexCAN module and CAN messages are being received at the time. So I suspect it is something to do with that!

[1430611548]

I found the same problem.  And I had used a lot of time to fix the problem. After scanned this acticle. I modified the MQX source to change the same level interrupt to different one. Then it is ok, no unhandled interrupt occurs.

[SoftwareForHire]

I have the same issue.

I am also using the FlexCAN module and have messages being received about every 50ms. This interrupt only triggers on my code when I hit a breakpoint and then try to resume execution. At the time I resume execution , the interrupt occurs.

I have been able to temporarily work around the problem by actually installing an interrupt handler for the MCF5225_INT1_rsvd31 interrupt (I am just using my regular FlexCAN_ISR interrupt handler).

To make this work, I had to modify the M52259ev.h file and change the BSP_LAST_INTERRUPT_VECTOR_USED value to be MCF5225_INT1_rsvd31 and then rebuild MQX.

This seems to fix the problem (at least for now). 

It sems to me that there is a real (undocumented) interrupt happening. Iit appears to me to be some kind of CAN overrun error that is occurring while I am sitting at a breakpoint in the debugger.

I plan on submitting a problem report to see what can be done about it.

[lumi]

Hello SoftwareForHire,

I have the exact same problem. I'll try what you did. 

Did you finally get an answer from Freescale?

Help is appreciated.

[SoftwareForHire]

I don't remember ever seeing an answer. We used the solution that I came up with for production.

[lumi]

So be it. I'll give it a try. I posted a Technical Service Request, hopefully these guys make a good job in clarifying why in the world we're getting an interrupt caused by --supposedly-- unused sources. I'm getting unhandled interrupts from vectors 151, 157 and 159 very consistently.

Thanks for you prompt reply!

[lumi · Accepted solution]

I found the problem. I hope this helps to all other people experiencing it.

- First the MCF52259 microcontroller device --possible others, too-- has some undeterministic behavior when the ICR registers are set to the same values. "MCF52259 ColdFire® Integrated Microcontroller Reference Manual, Rev. 4", page 16-10 states: "It is the responsibility of the software to program the ICRnx registers with unique and non-overlapping level and priority definitions. Failure to program the ICRnx registers in this manner can result in undefined behavior."

I find this as a major drawback on the device design. A microcontroller should be a deterministic machine. There should be a mechanism that solves concurrent interrupts of the same configured priority.

- Second, MQX does exactly what the manual says not to do. In function FLEXCAN_Int_enable, called as follows:

FLEXCAN_Initialize_mailbox -> FLEXCAN_Int_enable -> _flexcan_int_init

... the ICRs associated with the CAN mailboxes are set to a predefined interrupt level and sub-level...

Check: _flexcan_int_init (index, FLEXCAN_MESSBUF_INT_LEVEL, FLEXCAN_MESSBUF_INT_SUBLEVEL, TRUE)

This caused a our application - heavily dependant on CAN @500 kbps- to generate continuous resets and therefore to not function at all.

I think that Freescale needs to address this issue in their next  MQX release.

My setup:

MCF52259 in a custom developed board, using CAN @ 500 kBit/s

CodeWarrior 10.2

MQX 3.8

[DavidS]

Hi lumi,

Sorry for the hassles and thank you for posting your solution.

I will forward this to our MQWX Development team.

Regards,

David

[lumi]

Hi,

How interesting. Just updated our app to use the latest MQX and suddenly things started failing... I started getting some occasional unhandled exceptions and all this strange behavior sounded kind of familiar. After a little investigation I come to the forum, see my own solution, go check the MQX CAN driver and find that in version 4.0.2 it still has the same error.

The line...

     _flexcan_int_init (index, FLEXCAN_MESSBUF_INT_LEVEL, FLEXCAN_MESSBUF_INT_SUBLEVEL, TRUE)

... does exactly what the manual says not to do: setting the same interrupt level and sublevel to different exception sources.

Freescale: Please resolve this bug in MQX!

Thanks,

Luis

[DavidS]

Hi Fenz,

Usually when a weird ISR occurs like you are seeing it is related to the stack getting corrupted (in my personal experience).

Make sure your tasks have plenety of stack space for debug then reduce them later.

Best Regards,

David