int32_t recv(uint8_t sn, uint8_t * buf, uint16_t len)
{
   uint8_t  tmp = 0;
   uint16_t recvsize = 0;
//A20150601 : For integarating with W5300
#if   _WIZCHIP_ == 5300
   uint8_t head[2];
   uint16_t mr;
#endif
//
   CHECK_SOCKNUM();
   CHECK_SOCKMODE(Sn_MR_TCP);
   CHECK_SOCKDATA();

   recvsize = getSn_RxMAX(sn);
   if(recvsize < len) len = recvsize;

//A20150601 : For Integrating with W5300
#if _WIZCHIP_ == 5300
   //sock_pack_info[sn] = PACK_COMPLETED;    // for clear
   if(sock_remained_size[sn] == 0)
   {
#endif
//
      while(1)
      {
         recvsize = getSn_RX_RSR(sn);
         tmp = getSn_SR(sn);
         if (tmp != SOCK_ESTABLISHED)
         {
            if(tmp == SOCK_CLOSE_WAIT)
            {
               if(recvsize != 0) break;
               else if(getSn_TX_FSR(sn) == getSn_TxMAX(sn))
               {
                  close(sn);
                  return SOCKERR_SOCKSTATUS;
               }
            }
            else
            {
               close(sn);
               return SOCKERR_SOCKSTATUS;
            }
         }
         if((sock_io_mode & (1<<sn)) && (recvsize == 0)) return SOCK_BUSY;
         if(recvsize != 0) break;
      };
#if _WIZCHIP_ == 5300
   }
#endif

//A20150601 : For integrating with W5300
#if _WIZCHIP_ == 5300
   if((sock_remained_size[sn] == 0) || (getSn_MR(sn) & Sn_MR_ALIGN))
   {
      mr = getMR();
      if((getSn_MR(sn) & Sn_MR_ALIGN)==0)
      {
         wiz_recv_data(sn,head,2);
         if(mr & MR_FS)
            recvsize = (((uint16_t)head[1]) << 8) | ((uint16_t)head[0]);
         else
            recvsize = (((uint16_t)head[0]) << 8) | ((uint16_t)head[1]);
         sock_pack_info[sn] = PACK_FIRST;
      }
      sock_remained_size[sn] = recvsize;
   }
   if(len > sock_remained_size[sn]) len = sock_remained_size[sn];
   recvsize = len;
   if(sock_pack_info[sn] & PACK_FIFOBYTE)
   {
      *buf = sock_remained_byte[sn];
      buf++;
      sock_pack_info[sn] &= ~(PACK_FIFOBYTE);
      recvsize -= 1;
      sock_remained_size[sn] -= 1;
   }
   if(recvsize != 0)
   {
      wiz_recv_data(sn, buf, recvsize);
      setSn_CR(sn,Sn_CR_RECV);
      while(getSn_CR(sn))
                   {DWT_Delay(2);} ;
   }
   sock_remained_size[sn] -= recvsize;
   if(sock_remained_size[sn] != 0)
   {
      sock_pack_info[sn] |= PACK_REMAINED;
      if(recvsize & 0x1) sock_pack_info[sn] |= PACK_FIFOBYTE;
   }
   else sock_pack_info[sn] = PACK_COMPLETED;
   if(getSn_MR(sn) & Sn_MR_ALIGN) sock_remained_size[sn] = 0;
   //len = recvsize;
#else
   if(recvsize < len) len = recvsize;
   wiz_recv_data(sn, buf, len);
   setSn_CR(sn,Sn_CR_RECV);
   while(getSn_CR(sn))
            {DWT_Delay(2);} ;
#endif

   //M20150409 : Explicit Type Casting
   //return len;
   return (int32_t)len;
}