TM4C123G Launchpad CAN TX Issue

Still  figuring out how to paste code snippets:

void

CANIntHandler(void)

{

uint32_t ui32Status;

//

// Read the CAN interrupt status to find the cause of the interrupt

//

ui32Status = CANIntStatus(CAN0_BASE, CAN_INT_STS_CAUSE);

//

// If the cause is a controller status interrupt, then get the status

//

if(ui32Status == CAN_INT_INTID_STATUS)

{

ui32Status = CANStatusGet(CAN0_BASE, CAN_STS_CONTROL);

//

// Set a flag to indicate some errors may have occurred.

//

g_bErrFlag = 1;

}

//

// Check if the cause is message object 1, which what we are using for

// sending messages.

//

else if(ui32Status == 1)

{

//

// Getting to this point means that the TX interrupt occurred on// message object 1, and the message TX is complete. Clear the// message object interrupt.

//

CANIntClear(CAN0_BASE, 1);

// Increment a counter to keep track of how many messages have been sent.

g_ui32MsgCount++;

//

// Since the message was sent, clear any error flags.

//

g_bErrFlag = 0;

}

//

// Otherwise, something unexpected caused the interrupt. This should

// never happen.

//

else

{

//

// Spurious interrupt handling can go here.

//

}

}

ui32MsgData = 0;

sCANMessage.ui32MsgID = 1;

sCANMessage.ui32MsgIDMask = 0;

sCANMessage.ui32Flags = MSG_OBJ_TX_INT_ENABLE;

sCANMessage.ui32MsgLen = sizeof(pui8MsgData);

sCANMessage.pui8MsgData = pui8MsgData;

 

 

while(1)

{

//

// Print a message to the console showing the message count and the

// contents of the message being sent.

//

UARTprintf("Sending msg: 0x%02X %02X %02X %02X",

pui8MsgData[0], pui8MsgData[1], pui8MsgData[2],

pui8MsgData[3]);

//

// Send the CAN message using object number 1 (not the same thing as

// CAN ID, which is also 1 in this example). This function will cause

// the message to be transmitted right away.

//

CANMessageSet(CAN0_BASE, 1, &sCANMessage, MSG_OBJ_TYPE_TX);

//

// Now wait 1 second before continuing

//

SimpleDelay();

　

//

// Check the error flag to see if errors occurred

//

if(g_bErrFlag)

{

UARTprintf(" error - cable connected?\n");

}

else

{

//

// If no errors then print the count of message sent

//

UARTprintf(" total count = %u\n", g_ui32MsgCount);

}

//

// Increment the value in the message data.

//

ui32MsgData++;

}

//

// Return no errors

//

return(0);

}

 

Hello Sid,

If you are using TivaWare 2.1.3 then I would suggest reverting to the older version of TivaWare. This is an incorrect fix done in TivaWare which would be reverted.

Hi Amit, I cant seem to find a link to older versions, would be great if you could point me in the right direction.

Also for my understanding of the issue, would you be able to say where the problem lies. At the moment it appears to me that

among the 4 operations within the while(1) loop, ui32MsgData++ and the UARTprints seem to be happening approx every 1s but CANMessageSet() almost seems to be operating in a independent non-blocking thread. Is there a register setting or mode for the controller that I am missing where the CAN controller will operate like that?

I realize that I didn't include my CAN monitor UART output screenshots in the previous post so here they are

Thanks a lot for the help.

Sid

Hello Amit, No change. I dropped the file in driverlib and rebuilt the lib file and my project. Do I need the can header file as well?

Regards
Sid

Hello Sid

Did you use the driverlib.lib from the new path where it has been compiled?

OK my bad.....I forgot I moved the project into my workspace!

Everything works as expected now, thanks a lot for your help!

Regards
Sid