Program jump to DAbrt_Handler

Hi All,

I encountered a strange problem: when stepping over the following line of my code (also highlighted in bold in the code list), the PC goes to DAbt_Handler. I couldn't figure out why. Any help is highly appreciated.

I am using MDK 4.53. RTX is the RTOS being used. The code gives me trouble: fdpMsg->fdpDataLen = 30;

Thanks,

Charles

// FDP.c

#include <RTL.H>
#include <Net_Config.h>
#include <string.h>
#include "FDP.h"

extern U8 own_hw_adr[];
extern U8 lhost_name[];
extern LOCALM localm[];
/** External function from Ethernet MAC driver
  It should be threadsafe.
*/
extern void send_frame (OS_FRAME *frame);

typedef struct
{
  U8 dstMacAddr[ETH_ADRLEN];
  U8 srcMacAddr[ETH_ADRLEN];
  U16 ethType;
} ETH_HEADER;

typedef struct
{
  ETH_HEADER ethHeader;
  U8 fdpMsgType;
  U16 fdpDataLen;
  U8 data[1];
} FDP_FRAME;

enum FDP_MSG_TYPE
{
  REQUEST_IP_INFO = 1,
  RESPONSE_IP_INFO,
  CONFIGURE_NEW_IP,
  MSG_END,
};

typedef void (*FDP_MSG_PROC)(void);

static void fdpSendIpInfo(void);
static void fdpConfigNewIp(void);
/* Dummy function for not-need-response message */
static void fdpDummy(void) {};

static const FDP_MSG_PROC fdpMsgProcessor[MSG_END - 1] =
{
  &fdpSendIpInfo,
  &fdpDummy,
  &fdpConfigNewIp,
};

static U8 fdpBuf[FDP_MAX_FRAME_SIZE];
static BOOL fdpBufEmpty = __TRUE;

// Callback function for Ethernet MAC driver
BOOL fdpFrameReceived(OS_FRAME *frame)
{
  /* Check the Ethernet frame type */
  if ((frame->data[12] == FDP_ETH_TYPE_HIGH)
      && (frame->data[13] == FDP_ETH_TYPE_LOW))
  {
    if (fdpBufEmpty)
      memcpy(fdpBuf, frame, (frame->length + 4));
    fdpBufEmpty = __FALSE;
    return __TRUE;
  }
  else
    return __FALSE;
}

void fdpHandler(void)
{
  OS_FRAME *rxFrame = (OS_FRAME *)fdpBuf;
  FDP_FRAME *fdpMsg = (FDP_FRAME *)rxFrame->data;

  if (!fdpBufEmpty
      && (fdpMsg->fdpMsgType < MSG_END)
      && (fdpMsg->fdpMsgType > 0)
     )
    (fdpMsgProcessor[fdpMsg->fdpMsgType - 1])();

  fdpBufEmpty = __TRUE;
}

static void fdpSendIpInfo(void)
{
  OS_FRAME *rxFrame = (OS_FRAME *)fdpBuf;
  FDP_FRAME *fdpMsg = (FDP_FRAME *)rxFrame->data;

  /* copy source MAC address to destination MAC address */
  memcpy(fdpMsg->ethHeader.dstMacAddr, fdpMsg->ethHeader.srcMacAddr,
          ETH_ADRLEN);
  /* Copy this machine's MAC address to response frame's source MAC address */
  memcpy(fdpMsg->ethHeader.srcMacAddr, own_hw_adr, ETH_ADRLEN);
  fdpMsg->fdpMsgType = (U8)RESPONSE_IP_INFO;



  fdpMsg->fdpDataLen = 30;  => after this line, the program goes to DAbt_Hnadler



  memcpy(fdpMsg->data, &localm[NETIF_ETH], 30 /* sizeof(LOCALM) */);

  /* Ethernet header = 14 bytes, fdpMsgType = 1 byte, fdpDataLen = 2 bytes */
  U16 frameLen = 30 /* sizeof(LOCALM) */ + 14 + 1 + 2;
  if (frameLen < 60)
    /* Avoid small frame (size less than 64 bytes). send_frame automatically
    generate CRC (4 bytes) */
    rxFrame->length = 60;
  else
    rxFrame->length = frameLen;
  /* Send response */
  send_frame(rxFrame);

}

static void fdpConfigNewIp(void)
{
}