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TMS320F28035: CANBUS does not receive message

Part Number: TMS320F28035

Hi 

I tried canbus communication with note that the SPRA876 examples  ( I adopted for 2803x) 

I can send message with tx loop example but  I can't receive message with rx loop example

I changed some parts of code. I see the signal on Rx pin but I can't read  datas.

What is the mistake? Could you help me?

My code:

//
// Included Files
//
#include "DSP2803x_Device.h"     // Headerfile Include File
#include "DSP2803x_Examples.h"   // Examples Include File

#define TXCOUNT  100000            // Transmission will take place (TXCOUNT) times


long      RXCOUNT = 0;


void MBXwrA(void);
long      i;
long      loopcount = 0;

volatile struct MBOX *test;


int main(void)
{

  initMCUPeripherals();
  
  struct ECAN_REGS ECanaShadow;

    InitECan();

    InitECanGpio();
	
	
    EALLOW;
	
	// Zero out (or initialize) the entire MBX RAM area 

	MBXwrA();


    
/* Write to the MSGID field 0f CAN-A - MBX number is written as its MSGID */
	
    ECanaMboxes.MBOX1.MSGID.bit.STDMSGID = 1;
	
	
	/* Configure CAN-A Mailboxes as Receive mailboxes */

	ECanaShadow.CANMD.all = ECanaRegs.CANMD.all;	
	ECanaShadow.CANMD.bit.MD1 = 1;
	ECanaRegs.CANMD.all = ECanaShadow.CANMD.all; 
	


/* Enable Mailboxes */
	
	ECanaShadow.CANME.all = ECanaRegs.CANME.all;	
	  ECanaShadow.CANME.bit.ME1= 1;
	ECanaRegs.CANME.all = ECanaShadow.CANME.all; 
          while(1)
        {

         while(ECanaRegs.CANRMP.bit.RMP1 != 1) {}  // Wait for all RMPn to be set..
         ECanaRegs.CANRMP.all = 0xFFFFFFFF;            // Clear all RMPn bits and start
         RXCOUNT++ ;                                   // all over again...
         if(RXCOUNT==1000){break;}
        }
}


void MBXwrA()
    {

    volatile struct MBOX *Mailbox  = (void *) 0x6108; // for mailboxes 1


            Mailbox->MSGID.all = 0;
            Mailbox->MSGCTRL.all = 0;
            Mailbox->MDH.all = 0;
            Mailbox->MDL.all = 0;
            Mailbox = Mailbox + 1;


           *test = * Mailbox;
    }

InitECan function :

{

    /* Create a shadow register structure for the CAN control registers. This is
     needed, since only 32-bit access is allowed to these registers. 16-bit access
     to these registers could potentially corrupt the register contents or return
     false data. */

    struct ECAN_REGS ECanaShadow;

        EALLOW;     // EALLOW enables access to protected bits

    /* Configure eCAN RX and TX pins for CAN operation using eCAN regs*/

        ECanaShadow.CANTIOC.all = ECanaRegs.CANTIOC.all;
        ECanaShadow.CANTIOC.bit.TXFUNC = 1;
        ECanaRegs.CANTIOC.all = ECanaShadow.CANTIOC.all;

        ECanaShadow.CANRIOC.all = ECanaRegs.CANRIOC.all;
        ECanaShadow.CANRIOC.bit.RXFUNC = 1;
        ECanaRegs.CANRIOC.all = ECanaShadow.CANRIOC.all;

    /* Configure eCAN for HECC mode - (reqd to access mailboxes 16 thru 31) */
                                        // HECC mode also enables time-stamping feature

        ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
        ECanaShadow.CANMC.bit.SCB = 1;
        ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

    /* Initialize all bits of 'Message Control Register' to zero */
    // Some bits of MSGCTRL register come up in an unknown state. For proper operation,
    // all bits (including reserved bits) of MSGCTRL must be initialized to zero

        ECanaMboxes.MBOX0.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX1.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX2.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX3.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX4.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX5.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX6.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX7.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX8.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX9.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX10.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX11.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX12.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX13.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX14.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX15.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX16.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX17.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX18.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX19.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX20.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX21.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX22.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX23.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX24.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX25.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX26.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX27.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX28.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX29.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX30.MSGCTRL.all = 0x00000000;
        ECanaMboxes.MBOX31.MSGCTRL.all = 0x00000000;

    // TAn, RMPn, GIFn bits are all zero upon reset and are cleared again
    //  as a matter of precaution.

        ECanaRegs.CANTA.all = 0xFFFFFFFF;   /* Clear all TAn bits */

        ECanaRegs.CANRMP.all = 0xFFFFFFFF;  /* Clear all RMPn bits */

        ECanaRegs.CANGIF0.all = 0xFFFFFFFF; /* Clear all interrupt flag bits */
        ECanaRegs.CANGIF1.all = 0xFFFFFFFF;

    /* Configure bit timing parameters for eCANA*/

        ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
        ECanaShadow.CANMC.bit.CCR = 1 ;            // Set CCR = 1
        ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

        // Wait until the CPU has been granted permission to change the configuration registers
        do
        {
          ECanaShadow.CANES.all = ECanaRegs.CANES.all;
        } while(ECanaShadow.CANES.bit.CCE != 1 );       // Wait for CCE bit to be set..

        ECanaShadow.CANBTC.all = 0;
        /* The following block is only for 60 MHz SYSCLKOUT. (30 MHz CAN module clock Bit rate = 1 Mbps
           See Note at end of file. */

        ECanaShadow.CANBTC.bit.BRPREG = 7;
        ECanaShadow.CANBTC.bit.TSEG2REG = 2;
        ECanaShadow.CANBTC.bit.TSEG1REG = 10;

        ECanaShadow.CANBTC.bit.SAM = 1;
        ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all;

        ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
        ECanaShadow.CANMC.bit.CCR = 0 ;            // Set CCR = 0
        ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

        // Wait until the CPU no longer has permission to change the configuration registers
        do
        {
          ECanaShadow.CANES.all = ECanaRegs.CANES.all;
        } while(ECanaShadow.CANES.bit.CCE != 0 );       // Wait for CCE bit to be  cleared..

    /* Disable all Mailboxes  */
        ECanaRegs.CANME.all = 0;        // Required before writing the MSGIDs



        EDIS;
}

  • Hello,

                  Debugging your code is not something we can support on e2e. Please go over the debug tips in www.ti.com/lit/SPRACE5 carefully. I realize that document is for a different device. however, the tips are applicable for any CAN. Specifically, ensure the following:

    1. Bit-rate is exactly identical between the transmitter and receiver
    2. MSGID of the transmit and receive mailboxes are the same