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TM4C1294NCPDT: CAN TX Problem

vijayakumar sargunam1
Prodigy 200 points
Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: EK-TM4C1294XL

I tried to transmit ADC information from one TIVAC to another TIVAC through CAN bus. I attached the CAN Transmit code below. I cant able to transmit the information through CAN bus I got following errors plz help to to solve this

I am getting error code as 224 and shows CAN bus error even I tried to figure out through CRO but iam not getting any signal from CAN TX/RX pins PB0 and PB1

Here the CAN STS TXOK is still zero I dobubt whether my CAN controller is working or not

Here the CAN ERR TEC register shows 224 as code what does it mean clarify

CAN TX Code

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/adc.h"
#include "inc/hw_memmap.h"
#include "driverlib/uart.h"
#include "driverlib/pin_map.h"
#include "utils/uartstdio.h"
#include "inc/hw_can.h"
#include "inc/hw_ints.h"
#include "driverlib/can.h"
#include "driverlib/interrupt.h"
#include "utils/uartstdio.h"
unsigned int sysClock;

volatile bool errFlag = 0; // transmission error flag
unsigned int sysClock; // clockspeed in hz
volatile int status;
volatile bool errflag;
void CANIntHandler(void) {

    unsigned long status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE); // read interrupt status

    if(status == CAN_INT_INTID_STATUS) { // controller status interrupt
        status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL); // read back error bits, do something with them?

            errFlag = 1;
    } else if(status == 1) { // message object 1
        CANIntClear(CAN1_BASE, 1); // clear interrupt
        errFlag = 0; // clear any error flags
    } else { // should never happen
        UARTprintf("Unexpected CAN bus interrupt\n");
    }
}

void delay(unsigned int milliseconds) {
    SysCtlDelay((sysClock / 3) * (milliseconds / 1000.0f));
}
int main(void)
{
    uint32_t ui32ACCValues[4];
    volatile uint32_t ui32AccX;
    volatile uint32_t ui32AccY;
    volatile uint32_t ui32AccZ;
    tCANMsgObject msg; // the CAN message object
        unsigned int msgData; // the message data is four bytes long which we can allocate as an int32
        unsigned char *msgDataPtr = (unsigned char *)&msgData; // make a pointer to msgData so we can access individual bytes

    SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);

    sysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);

        // Set up debugging UART
        SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA); // enable UART0 GPIO peripheral
        SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
        GPIOPinConfigure(GPIO_PA0_U0RX);
        GPIOPinConfigure(GPIO_PA1_U0TX);
        GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
        UARTStdioConfig(0, 115200, sysClock); // 115200 baud

    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
    GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 );


    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);
    GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0|GPIO_PIN_1);


    ADCSequenceConfigure(ADC0_BASE, 1, ADC_TRIGGER_PROCESSOR, 0);
    ADCSequenceStepConfigure(ADC0_BASE, 1, 0, ADC_CTL_CH3);
    ADCSequenceStepConfigure(ADC0_BASE, 1, 1, ADC_CTL_CH2);
    ADCSequenceStepConfigure(ADC0_BASE, 1, 2, ADC_CTL_CH1|ADC_CTL_IE|ADC_CTL_END);

    ADCSequenceEnable(ADC0_BASE, 1);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // enable CAN1 GPIO peripheral
    GPIOPinConfigure(GPIO_PB0_CAN1RX);
    GPIOPinConfigure(GPIO_PB1_CAN1TX);
    GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);
    CANInit(CAN1_BASE);
    CANBitRateSet(CAN1_BASE, sysClock, 500000);
    CANIntRegister(CAN1_BASE, CANIntHandler); // use dynamic vector table allocation
    CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
    CANIntClear(CAN1_BASE,CAN_INT_STATUS);
    IntEnable(INT_CAN1);
    CANEnable(CAN1_BASE);

    // Set up msg object
    msgData = 0;
    msg.ui32MsgID = 1;
    msg.ui32MsgIDMask = 0;
    msg.ui32Flags = MSG_OBJ_TX_INT_ENABLE;
    msg.ui32MsgLen = sizeof(msgDataPtr);
    msg.pui8MsgData = msgDataPtr;


    while(1)
    {
        ADCIntClear(ADC0_BASE, 1);
        ADCProcessorTrigger(ADC0_BASE, 1);
        while(!ADCIntStatus(ADC0_BASE, 1, false))
        {
        }
        ADCSequenceDataGet(ADC0_BASE, 1, ui32ACCValues);
        msgDataPtr[0] = (ui32ACCValues[0]/1023);
        msgDataPtr[1]= (ui32ACCValues[1]/1023);
        msgDataPtr[2]= (ui32ACCValues[2]/1023);
        UARTprintf("\nAnalog Voltage\tR: %d\tY: %d\tB: %d\n",msgDataPtr[0],msgDataPtr[1],msgDataPtr[2]); // write colour to UART for debugging
/*if (msgDataPtr[0]>=3)
{
     GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0);
     GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_1, 0x0);
    UARTprintf("\nCondition is True");
   }
else
{
            GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_1,GPIO_PIN_1 );
            GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0x0);
 //  UARTprintf("\nCondition is False");
}*/
        CANMessageSet(CAN1_BASE, 1, &msg, MSG_OBJ_TYPE_TX); // send as msg object 1

                delay(100); // wait 100ms

                if(errFlag) { // check for errors
                   UARTprintf("CAN Bus Error\n");

                    UARTprintf("\nError Code:%d",CANStatusGet(CAN1_BASE, CAN_STS_CONTROL));
                }

        delay(1000); // wait 100ms
    }
    return 0;
}

CAN Receive code

/*
 * CAN bus LED controller slave firmware
 * Written for TI Tiva TM4C123GH6PM
 */

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/adc.h"
#include "inc/hw_memmap.h"
#include "driverlib/uart.h"
#include "driverlib/pin_map.h"
#include "utils/uartstdio.h"
#include "inc/hw_can.h"
#include "inc/hw_ints.h"
#include "driverlib/can.h"
#include "driverlib/interrupt.h"
#include "utils/uartstdio.h"

volatile bool rxFlag = 0; // msg recieved flag
volatile bool errFlag = 0; // error flag

// CAN interrupt handler
void CANIntHandler(void) {

    unsigned long status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE); // read interrupt status

    if(status == CAN_INT_INTID_STATUS) { // controller status interrupt
        status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL);
        errFlag = 1;
    } else if(status == 1) { // msg object 1
        CANIntClear(CAN1_BASE, 1); // clear interrupt
        rxFlag = 1; // set rx flag
        errFlag = 0; // clear any error flags
    } else { // should never happen
        UARTprintf("Unexpected CAN bus interrupt\n");
    }
}

int main(void) {

    tCANMsgObject msg; // the CAN msg object
    unsigned char msgData[8]; // 8 byte buffer for rx message data

    // Run from crystal at 50Mhz
    SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);

    // Set up debugging UART
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    UARTStdioConfig(0, 115200, 120000000);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // enable CAN1 GPIO peripheral
    GPIOPinConfigure(GPIO_PB0_CAN1RX);
    GPIOPinConfigure(GPIO_PB1_CAN1TX);
    GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);
    CANInit(CAN1_BASE);
    CANBitRateSet(CAN1_BASE, 120000000, 500000);
    CANIntRegister(CAN1_BASE, CANIntHandler); // use dynamic vector table allocation
    CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
    CANIntClear(CAN1_BASE,CAN_INT_STATUS);
    IntEnable(INT_CAN1);
    CANEnable(CAN1_BASE);


      // Use ID and mask 0 to recieved messages with any CAN ID
    msg.ui32MsgID = 0;
    msg.ui32MsgIDMask = 0;
    msg.ui32Flags = MSG_OBJ_RX_INT_ENABLE | MSG_OBJ_USE_ID_FILTER;
    msg.ui32MsgLen = 8; // allow up to 8 bytes

    // Load msg into CAN peripheral message object 1 so it can trigger interrupts on any matched rx messages
    CANMessageSet(CAN1_BASE, 1, &msg, MSG_OBJ_TYPE_RX);

    unsigned int colour[3];
    float intensity;

    while(1) {

        if(rxFlag) { // rx interrupt has occured

            msg.pui8MsgData = msgData; // set pointer to rx buffer
            CANMessageGet(CAN1_BASE, 1, &msg, 0); // read CAN message object 1 from CAN peripheral

            rxFlag = 0; // clear rx flag

            if(msg.ui32Flags & MSG_OBJ_DATA_LOST) { // check msg flags for any lost messages
                UARTprintf("CAN message loss detected\n");
            }

            // read in colour data from rx buffer (scale from 0-255 to 0-0xFFFF for LED driver)
            colour[0] = msgData[0] * 0xFF;
            colour[1] = msgData[1] * 0xFF;
            colour[2] = msgData[2] * 0xFF;
            intensity = msgData[3] / 255.0f; // scale from 0-255 to float 0-1

            // write to UART for debugging
            UARTprintf("Received colour\tr: %d\tg: %d\tb: %d\ti: %d\n", msgData[0], msgData[1], msgData[2], msgData[3]);
}}}
            // set colour and intensity
            //RGBSet(colour, intensity);
        }
    }

    return 0;
}

iam not getting any information in receiver side the rxflag not getting any interrupt from transmitter side

  • 0
    TI__Guru 72500 points
    The status bits show that the CAN transmitter is bus off. I suspect this is because you have not connected the CAN bus properly and the bus is permanently in the dominate state or when the transmitter tries to output a dominate (CANTX low), it reads a recessive (CANRX high). You cannot just connect CANTX from one device to CANRX on another. You must have a proper CAN bus with transceivers and termination resistors. Here is some information about how to create a CAN bus:
    www.ti.com/.../sloa101b.pdf
  • 0 in reply to Bob Crosby
    Prodigy 200 points

    Dear Crosby,

                        Thanks for your suggestion. I am using MCP2551 transceivers for communicating between two TIVAC (TM4C1294NCPDT). I can able to transmit the data from transmitter. but i did n't get anything from receiver

    Transmitter signal

    The transmitter register window shown below


    During receiving CAN message loss was detected. I do step over to check whether i can able to receive any thing but it is not properly receiving the transmitted signal

    received signal


    When i press resume button i got the following output

    I guess the problem may be in the receiver code or in the connection plz do help me

    /*
 * CAN bus LED controller slave firmware
 * Written for TI Tiva TM4C1294NCPDT
 */

#include <stdint.h>
#include <stdbool.h>

#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_can.h"
#include "inc/hw_ints.h"
#include "driverlib/can.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/uart.h"
#include "driverlib/pin_map.h"

#include "utils/uartstdio.h"
//#include "drivers/rgb.h"

volatile bool rxFlag = 0; // msg recieved flag
volatile bool errFlag = 0; // error flag
unsigned int sysClock; // clockspeed in hz

// CAN interrupt handler
void CANIntHandler(void) {

   unsigned long status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE); // read interrupt status

   if(status == CAN_INT_INTID_STATUS) { // controller status interrupt
      status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL);
      errFlag = 1;
   } else if(status == 1) { // msg object 1
      CANIntClear(CAN1_BASE, 1); // clear interrupt
      rxFlag = 1; // set rx flag
      errFlag = 0; // clear any error flags
   } else { // should never happen
      UARTprintf("Unexpected CAN bus interrupt\n");
   }
}

int main(void) {

   tCANMsgObject msg; // the CAN msg object
   unsigned char msgData[8]; // 8 byte buffer for rx message data

   // Run from crystal at 50Mhz
    sysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);

   // Set up debugging UART
   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
   GPIOPinConfigure(GPIO_PA0_U0RX);
   GPIOPinConfigure(GPIO_PA1_U0TX);
   GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
   UARTStdioConfig(0, 115200, sysClock); // 115200 baud


   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // enable CAN1 GPIO peripheral
   GPIOPinConfigure(GPIO_PB0_CAN1RX);
   GPIOPinConfigure(GPIO_PB1_CAN1TX);
   GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);
   CANInit(CAN1_BASE);
   CANBitRateSet(CAN1_BASE, sysClock, 500000);
   CANIntRegister(CAN1_BASE, CANIntHandler); // use dynamic vector table allocation
   CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
   IntEnable(INT_CAN1);
   CANEnable(CAN1_BASE);

   // Set up LED driver
//   RGBInit(1);

   // Use ID and mask 0 to recieved messages with any CAN ID
   msg.ui32MsgID = 0;
   msg.ui32MsgIDMask = 0;
   msg.ui32Flags = MSG_OBJ_RX_INT_ENABLE | MSG_OBJ_USE_ID_FILTER;
   msg.ui32MsgLen = 8; // allow up to 8 bytes

   // Load msg into CAN peripheral message object 1 so it can trigger interrupts on any matched rx messages
   CANMessageSet(CAN1_BASE, 1, &msg, MSG_OBJ_TYPE_RX);

   unsigned int colour[3];
   float intensity;

   while(1) {

      if(rxFlag) { // rx interrupt has occured

         msg.pui8MsgData = msgData; // set pointer to rx buffer
         CANMessageGet(CAN1_BASE, 1, &msg, 0); // read CAN message object 1 from CAN peripheral

         rxFlag = 0; // clear rx flag

         if(msg.ui32Flags & MSG_OBJ_DATA_LOST) { // check msg flags for any lost messages
            UARTprintf("CAN message loss detected\n");
         }

         // read in colour data from rx buffer (scale from 0-255 to 0-0xFFFF for LED driver)
         colour[0] = msgData[0] * 0xFF;
         colour[1] = msgData[1] * 0xFF;
         colour[2] = msgData[2] * 0xFF;
         intensity = msgData[3] / 255.0f; // scale from 0-255 to float 0-1

         // write to UART for debugging
         UARTprintf("Received colour\tr: %d\tg: %d\tb: %d\ti: %d\n", colour[0], colour[1], colour[2], intensity);

         // set colour and intensity
         //RGBSet(colour, intensity);
      }
      else
      {
UARTprintf("not received anything");
      }
   }

   //return 0;
}

    Project experiment setup



     

     

     

  • 0 in reply to vijayakumar sargunam1
    TI__Guru 72500 points
    Do you somewhere have the call to "IntMasterEnable()"?
  • 0 in reply to vijayakumar sargunam1
    Guru 55913 points

    Hello,

    vijayakumar sargunam1 said:
    When i press resume button i got the following output

    UARTprintf() rolls crazy inside while loop can cause application crash issues if buffer floods.

    Try adding Boolean flag so error message/s only prints once unless it changes.

    #if DEBUG
      	if(bMsgFlag == 0)
       	{
          UARTprintf("Print one message only \n");

          bMsgFlag = 1;
        }
#endif

  • 0 in reply to Bob Crosby
    Prodigy 200 points

    hi bob,

                 I  added the IntMasterEnable() fuction in the receiver code like below

    but still iam not able to get the output. I wonder why message loss has occurred in receiver side. whether it is due to hardware or software clarify me plz

  • 0 in reply to Genatco
    Prodigy 200 points

    Hi BP101,

                  I added the code snippet in the else part once I added it the serial window is blank not even error message is displayed. and also I step into the code it shows the RX interrupt never occurred and it stays there itself.

  • 0 in reply to vijayakumar sargunam1
    TI__Guru 72500 points

    Did you check the voltage on the PB1 pins? Remember that on the EK-TM4C1294XL that pin is used as the USB OTG VBUS signal and is attached to 5V. The schematic is here:

    http://www.ti.com/lit/ug/spmu365c/spmu365c.pdf#page=31

  • 0 in reply to Bob Crosby
    Prodigy 200 points

    Hi bob,

               finally I got the output as you told I added the IntMasterEnable(); function in the transmitter code instead of receiver code. As well as BP101 gave me some suggestion regarding the if loop condition in the receiver code. When I added both of your suggestion I got the output immediately. Thanks both of you for your guidance.

  • 0 in reply to vijayakumar sargunam1
    Guru 55913 points

    vijayakumar sargunam1 said:
    I got the output as you told I added the IntMasterEnable();

    Perhaps Bob can explain why the IntMasterEnable() is even required when the CAN peripheral interrupt was being enabled. I had thought Master performed a NVIC global function when ALL interrupts need be enabled or disabled at the same time. Past had tried to use Master to bulk control enabled peripheral INTS in a function and two Master disabled INTS kept pending until they were disabled at the peripheral level too. Seems a bit misplaced to have both Master & peripheral INT controls to immediately stop the peripheral from pending when Master alone should stop pends. 

  • 0 in reply to Genatco
    TI__Guru 72500 points
    The architecture has three levels of enable for the interrupts, the peripheral (ex: CANIntEnable(…);), the vectored interrupt module, VIM, (ex: IntEnable(INT_CAN1);) and the CPU (ex: IntMasterEnable(); )