problem in ethernet transmission using dm6437 dvdp

Rutcha,

I assume that you are trying to transmit TX_SIZE bytes of data, but the packet descriptors are telling EMAC to transmit 1514 bytes.  Is TX_SIZE equal to 1514?

-Michael

hi....

no TX_SIZE = 1498 i.e. 1514-16 bytes of header. so each packet contains 1498 bytes of data.

Rutcha,

The packet size that you program into the descriptors should include some header-type data bytes like DST ADDR, SRC ADDR, and LEN.  Please ensure that this is handled in the program.  You can see a figure of the frame in Section 2.4.1 of the EMAC user guide (spru941a).

Do you have a simple application that is able to transmit EMAC packets in a way that matches your expectations?  We can use that as a starting point to isolate the problem.

-Mike

yes I have included the dst and src addresses in header and I have tested the simple application to send ethernet packets :

#include "emac.h"

#define TX_BUF    1514//////
#define RX_BUF    1536

Uint8 packet_data[TX_BUF];
void* ptr;//////
Uint8 packet_buffer1[RX_BUF];
Uint8 packet_buffer2[RX_BUF];
Uint8 packet_buffer3[RX_BUF];
Uint8 packet_buffer4[RX_BUF];
Uint8 packet_buffer5[RX_BUF];
Uint8 packet_buffer6[RX_BUF];
Uint8 packet_buffer7[RX_BUF];
Uint8 packet_buffer8[RX_BUF];
Uint8 packet_buffer9[RX_BUF];
Uint8 packet_buffer10[RX_BUF];

/*
 *  We use pDescBase for a base address. Its easier this way
 *  because we can use indexing off the pointer.
 */
EMAC_Desc* pDescBase = ( EMAC_Desc* )EMAC_RAM_BASE;

/*
 *  The following are used to allow the ISR to communicate with
 *  the application.
 */
extern volatile int RxCount;
extern volatile int TxCount;
extern volatile int ErrCount;
extern volatile EMAC_Desc *pDescRx;
extern volatile EMAC_Desc *pDescTx;
extern Uint8* dest;
Int16 verify_packet( EMAC_Desc* pDesc, Uint32 size, Uint32 flagCRC );

/* ------------------------------------------------------------------------ *
 *                                                                          *
 *  emac_test                                                               *
 *      EMAC tests to send data to external loopback cable.                 *
 *                                                                          *
 * ------------------------------------------------------------------------ */
Int16 emac_test( )
{
    Int32 i;
    Int16 errors = 0;
    Uint32 status;

    Int32 emac_timeout = 0x100000;
    Int32 timeout;
    EMAC_Desc* pDesc;
 dest = (void*)dest;      //one frame data

    /* ---------------------------------------------------------------- *
     *                                                                  *
     *  Setup EMAC                                                      *
     *                                                                  *
     * ---------------------------------------------------------------- */
    emac_init( );
* ---------------------------------------------------------------- *
     *         
                                                              *
     *  Setup TX packets                                                *
     *      Send 2 copies of the same packet using different sizes      *
     *                                                                  *
     * ---------------------------------------------------------------- */
  packet_data[0]=0x00;//
  packet_data[1]=0x11;//
  packet_data[2]=0x2F;//
  packet_data[3]=0xF4;
  packet_data[4]=0x6F;
  packet_data[5]=0x28;
  packet_data[6]=0x00;
  packet_data[7]=0x0E;
  packet_data[8]=0x99;
  packet_data[9]=0x02;
  packet_data[10]=0x99;
  packet_data[11]=0x3C;
  packet_data[12]=0x08;
  packet_data[13]=0x09;
  packet_data[14]=0x00;
  packet_data[15]=0x00;
   // for ( i = 12 ; i < TX_BUF ; i++ )  ////////////////
   //     packet_data[i] = i;
  
 for (i=0 ; i<553; i++)/////
{ 

    ptr = & packet_data[16];
 memcpy(ptr, dest+1498 * i,1498);
    pDesc            = pDescBase + 10;
    pDesc->pNext     = 0;////////
    pDesc->pBuffer   = packet_data;
    pDesc->BufOffLen = 1514;
    pDesc->PktFlgLen = EMAC_DSC_FLAG_OWNER
                     | EMAC_DSC_FLAG_SOP
                     | EMAC_DSC_FLAG_EOP
                     | 1514;
 

      /*
     *  Start TX sending
     */
    pDescTx = pDescBase + 10;
    EMAC_TX0HDP = ( Uint32 )pDescTx;

    /* ---------------------------------------------------------------- *
     *                                                                  *
     *  Normally there would be a interrupt to service the EMAC RX/TX   *
     *  transmission.  Instead a short pause and manually call the ISR  *
     *  Interrupt Service Routine to check on the status.               *
     *                                                                  *
     *  You can later add in the ISR and the code to support.           *
     *                                                                  *
     * ---------------------------------------------------------------- */

    /* Busy period */
    _wait( 10000 );

    /* Manually check ISR, if using interrupts this will be done automatically */
    EMAC_isr( );
}

Thanks Rutcha.  The example really helps me put your code snippet into context.

Are you receiving the correct number of packets?

Instead of the _wait() statement, can you try a while loop to poll for any of the following:
  a) while( pDesc->PktFlgLen | EMAC_DSC_FLAG_OWNER );
  b) while( EMAC_TX0CP != (Uint32) pDescTx );  /* EMAC_TX0CP should be zero before the packet is transmitted */
  c) tmpInt = EMAC_TXGOODFRAMES; while( EMAC_TXGOODFRAMES == tmpInt );

I've also just started working on communicating two evmdm6437 boards through ethernet, and for starters i need to know where can i find that emac.pjt project so needed for implementing this!

Kindly help!