TMS320F280049: LIN communication is stopped after increase working load

Daniel,

            This appears to be more of EMI issue than a LIN issue to me.

1. If you progressively increase the load, does LIN keep working but fails only around 20 A? That is, does it work from 0A to 20A?
2. Are you monitoring LIN bus traffic using a bus analyzer?
3. Do you see any errors on the bus before LIN communication stops?
4. Is any other part of the chip affected or is it only the LIN module?
5. How about other communication peripherals?

Hi Hareesh,

Thanks for your reply. Answer your questions firstly.

1. LIN keep working at low load, but will lose frames at high load.

2. Sorry for we hasn't bus analyzer.

3. No errors observed before LIN stops

4. When LIN stops, DCDC still can works.

5. No other communication peripheral are used now.

During debug in this days, we make a improvement at 37A full load after make changes in below code:

LIN communication keep works at 37A full load. But it sill has some frame lost.

When master node writes, use LIN_isSCIDataAvailable(LINA_BASE) function to help communication be recovered when it is interrupted.

if(LIN_isSCIDataAvailable(LINA_BASE))
     {
//        if(LINpara.vectorOffset == LIN_VECT_RX)
//        {
        RXID.RX_WAKEUP++;
         RXID.byte1=LIN_getRxIdentifier(LINA_BASE);
         switch(RXID.byte1)
         {
             case 0x06:
                 CANBUSOFFPARA.OvertimeCntRX_06=0;
                 HVSC_0x06RcvManage();
                 break;
             case 0xC1:
                 CANBUSOFFPARA.OvertimeCntRX_01=0;
                 HVSC_0x01RcvManage();
                 break;
             case 0x20:
                 CANBUSOFFPARA.OvertimeCntRX_20=0;
                 UDS_Lin_RX_Interface();
                break;
             default: break;
         }
         LINpara.vectorOffset=0;
     }
     else{;}

What we have test:

1. Capture input and output current and voltage. When communication is lost, there is no jump occurs, exclude that is caused by input and output load problems.

2. Monitor the interruption used by DCDC, monitor adc_isr, epwm1_tz_isr, cpu_timer0_isr respectively. We find that the adc_isr interruption is less be used, add LED in code to detect the time. When the load can not be increased, observe it by oscilloscope. Reduce the frequency to run adc_isr, the frame loss is still occurs. Thanks.

Hi Daniel,

What improvement did you make for LIN to work upto 37A of loading? Based on your initial post it was not working at 20A, correct? 

Just trying to understand the problem. Like Hareesh mentioned it appears to be EMI related.

Regards,

Nirav

Hi Nirav and Hareesh,

To be simple, my customer has to use LIN polling mode instead of interruption example

1. Could you provide a LIN polling mode example?

2.  If not, could you help check below polling code customer write? Thanks.

Call LIN_isSCIDataAvailable(LINA_BASE) for writing.

void LIN_RXProcess(void)
{

    if(LIN_isSCIDataAvailable(LINA_BASE))
     {
        if(LINpara.vectorOffset == LIN_VECT_RX)
        {
        RXID.RX_WAKEUP++;
         RXID.byte1=LIN_getRxIdentifier(LINA_BASE);
         switch(RXID.byte1)
         {
             case 0x06:
                 CANBUSOFFPARA.OvertimeCntRX_06=0;
                 RXID.byte4++;
                 HVSC_0x06RcvManage();
                 break;
             case 0xC1:
                 CANBUSOFFPARA.OvertimeCntRX_01=0;
                 RXID.byte5++;
                 HVSC_0x01RcvManage();
                 break;
             case 0x20:
                 CANBUSOFFPARA.OvertimeCntRX_20=0;
                 UDS_Lin_RX_Interface();
                break;
             default: break;
         }
         LINpara.vectorOffset=0;
     }
     else{;}
}

Call LIN_isRxMatch(LINA_BASE) for reading.

void LIN_TXProcess(void)
{
        if(LIN_isRxMatch(LINA_BASE))
         {
            RXID.RX_WAKEUP++;
             RXID.byte1=LIN_getRxIdentifier(LINA_BASE);
             switch(RXID.byte1)
             {              
             case 0x03:
                 CANBUSOFFPARA.OvertimeCntTX_03=0;
                 HVSC_0x03TrmManage();

                 break;
             case 0x85: //initial system
                 CANBUSOFFPARA.OvertimeCntTX_05=0;
                 HVSC_0x05TrmManage();

                 break;
             case 0x61:
                 CANBUSOFFPARA.OvertimeCntTX_21=0;
                 UDS_Lin_TX_Interface();
                 break;
             default: break;
         }
         LINpara.vectorOffset=0;
     }
     else{;}
}