TDA2P-ACD: CAN Disconnect

Hi Gokul,

Looks like exception happens in the ISS Capture Driver Call-back when you connect CAN again. Is there any dependency between Capture and MCAN link?

Also, can you please step through the 'Utils_mbxSendCmd()' and see where it is returning failure to print error message?

Thanks & Regards,
Vivek Dhande.

Texas Instruments (India) Pvt Ltd

Hi Vivek,

I don't find any dependency between CAN and Capture link. Also  Utils_mbxGetFreeMsgCount returns 0 , in  the  below printf

Vps_printf(" UTILS: MBX: Utils_mbxSendCmd(): Msg Alloc Failed "
"(%d)!!!\n", Utils_mbxGetFreeMsgCount());

Regards,

Gokul

Hi Gokul,

Does 'Utils_mbxGetFreeMsgCount()' returning '0' mean all the mailboxes for Tx messages are already occupied? If yes, then looks like error handling is needed in the application? Are you doing this? When you disconnect CAN node, TDA device will start throwing errors if any messages are sent after this.

If message transmission fails, what are the actions taken in the application? 

Thanks & Regards,
Vivek Dhande.

Texas Instruments (India) Pvt Ltd

Hi Vivek,

When we do disconnect, it is blocked in transmitMsgOverMCAN function. There is a while loop in this function,

/* wait untill transmit complete occurs */
while (gMcanTxIsrFlag)
{}
gMcanTxIsrFlag = 1U;

 When I spoke to Harman CAN team, they said it is expecting for  ACK . Since we do the PCAN- disconnection , the transmitter is not able to able to pull the ACK low.

Is there way to come out of this loop after some definite times .

It is part of the PDK -driver code. 

int32_t transmitMsgOverMCAN(MCAN_TxBufElement *txMsg )
{
int32_t status = STW_EFAIL, protocolStatus = STW_SOK;
MCAN_ProtocolStatus protStatus;

/* Enable Transmission interrupt */
status = MCAN_txBufTransIntrEnable(MCAN_MODULE,
1U,
(uint32_t)TRUE);

/* write the message into MessageRAM for transmission */
MCAN_writeMsgRam(MCAN_MODULE,
MCAN_MEM_TYPE_BUF,
1U,
txMsg);

/* Add request for transmission */
status += MCAN_txBufAddReq(MCAN_MODULE, 1U);
if (STW_SOK != status)
{
status = STW_EFAIL;
//UARTConfigPuts("\nError in Adding Transmission Request...\n");
}

/* wait untill transmit complete occurs */
while (gMcanTxIsrFlag)
{}
gMcanTxIsrFlag = 1U;

/* check for errors */
MCAN_getProtocolStatus(MCAN_MODULE, &protStatus);
/* Checking for Errors */
if (((MCAN_ERR_CODE_NO_ERROR == protStatus.lastErrCode) ||
(MCAN_ERR_CODE_NO_CHANGE == protStatus.lastErrCode)) &&
((MCAN_ERR_CODE_NO_ERROR == protStatus.dlec) ||
(MCAN_ERR_CODE_NO_CHANGE == protStatus.dlec)) &&
(0U == protStatus.pxe))
{
// no errors;
}
else
{
protocolStatus = STW_EFAIL;
}

if(STW_EFAIL == protocolStatus)
{
status = protocolStatus;
}

return status;
}

Regards,

Gokul

Hi Gokul,

Can you use semaphores instead of 'while (gMcanTxIsrFlag)' busy loop? This will allow other tasks to run even after the MCAN messages fail to go out.

Also, in the ISR where 'gMcanTxIsrFlag' gets set, looks like you are handling only successful transmit condition and not the failure.

Also, one more question does CAN and capture link runs on the same core? If yes, then it explains the hang after CAN disconnection.

Thanks & Regards,
Vivek Dhande.

Texas Instruments (India) Pvt Ltd

Hi Gokul,

    Were you able to try the above suggestion? Did it help?

Thanks & Regards,

Vivek Dhande.

Texas Instruments (India) Pvt Ltd

Hi Vivek,

Please give us some time on this. Our CAN  team  member is on Vacation. 

Regards,

Gokul

Hi Vivek,

Will Transmission Cancellation Finished bit be set  during  disconnection of the CAN ?

We need to handle the failure condition. 

void mcanTxISR(void)
{
uint32_t intrStatus;

intrStatus = MCAN_getIntrStatus(MCAN_MODULE);
MCAN_clearIntrStatus(MCAN_MODULE, intrStatus);
if (MCAN_INTR_SRC_TRANS_COMPLETE ==
(intrStatus & MCAN_INTR_SRC_TRANS_COMPLETE))
{
++can_isr_tx_success_counter;
resetTxIsrFlag();//gMcanTxIsrFlag = 0U;
}
else
{
Vps_printf(" UTILS: MCAN Tx Interrupt Status: %x !!!\n", intrStatus);
}
}