// TI Release: 28xx eCAN programming example
// Release Date: Fri Aug 4 2017
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/*********************************************************************
* Filename: TXLOOP_A.c                                                 *
*                                                                    *
* Description: TXLOOP - Transmit loop using any mailbox
*
* Mailbox 25 is shown as an example...
* This example TRANSMITS data to another CAN module using MAILBOX25
* This program could either loop forever or transmit "n" # of times,
* where "n" is the TXCOUNT value.
*
*********************************************************************/

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

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

long      i;
long      loopcount = 0;

main()
{

/* 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. This is
 especially true while writing to a bit (or group of bits) among bits 16 - 31 */

struct ECAN_REGS ECanaShadow;

/* Kill Watchdog, Init PLL, Enable peripheral clocks */

    InitSysCtrl();

/* Initialize the CAN module */

    InitECana();
    InitECanGpio();

    EALLOW;

/* Write to the MSGID field  */

    ECanaMboxes.MBOX0.MSGID.all = 0x9555AAA0; // Extended Identifier
    //ECanaMboxes.MBOX25.MSGID.bit.STDMSGID = 25;
/* Configure Mailbox under test as a Transmit mailbox */

    ECanaShadow.CANMD.all = ECanaRegs.CANMD.all;
    ECanaShadow.CANMD.all = 0x0000000;
    ECanaRegs.CANMD.all = ECanaShadow.CANMD.all;

/* Enable Mailbox under test */

    ECanaShadow.CANME.all = ECanaRegs.CANME.all;
    ECanaShadow.CANME.all = 1;
    ECanaRegs.CANME.all = ECanaShadow.CANME.all;

/* Write to DLC field in Message Control reg */

    ECanaMboxes.MBOX0.MSGCTRL.bit.DLC = 8;

/* Write to the mailbox RAM field */

     ECanaMboxes.MBOX0.MDL.all = 0x00000001;
     ECanaMboxes.MBOX0.MDH.all = 0x00000010;

/* Begin transmitting */

    while(1)                                // Uncomment this line for infinite transmissions
    //for(i=0; i < TXCOUNT; i++)                // Uncomment this line for finite transmissions
    {
     ECanaShadow.CANTRS.all = 0;
     ECanaShadow.CANTRS.bit.TRS0 = 1;     // Set TRS for mailbox under test
     ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all;

     ECanaShadow.CANTA.all = ECanaRegs.CANTA.all;
        do {ECanaShadow.CANTA.all = ECanaRegs.CANTA.all;}   // Wait for TA25 bit to be set..
         while(ECanaShadow.CANTA.bit.TA0 == 0 );

     ECanaShadow.CANTA.all = 0;
     ECanaShadow.CANTA.bit.TA0 = 1;         // Clear TA5
     ECanaRegs.CANTA.all = ECanaShadow.CANTA.all;

     loopcount ++;
    }

}


/* Notes:
A simple testcase that could be used to transmit data out of a mailbox


Last update: 7/22/2017     (Tested)
*/