2.3 stm32移植lwip常见问题和解决方式

 ETH_DeInit();

  /* Software reset */
  ETH_SoftwareReset();

  /* Wait for software reset */
  while (ETH_GetSoftwareResetStatus() == SET);

  /* ETHERNET Configuration---------------------------------------------*/
  /* Call ETH_StructInit if you don‘t like to configure all ETH_InitStructure parameter */
  ETH_StructInit(&ETH_InitStructure);

  /* Fill ETH_InitStructure parametrs */
  /*------------------------ ETH_MACCR-----------------------------------*/
    //参数是否自动配置，选择disable需要自动配置默写参数（auto模式在网线没插上时会导致超时，初始化失败）
  　ETH_InitStructure.ETH_AutoNegotiation = ETH_AutoNegotiation_Disable;
    ETH_InitStructure.ETH_Watchdog = ETH_Watchdog_Disable;                            //关闭看门狗定时器，允许接收超长帧
    ETH_InitStructure.ETH_Jabber = ETH_Jabber_Disable;                                //关闭jabber定时器，允许发送超长帧
    ETH_InitStructure.ETH_InterFrameGap = ETH_InterFrameGap_40Bit;          　　　　　　//发送帧间间隙
    ETH_InitStructure.ETH_Speed = ETH_Speed_100M;                                     //快速以太网速度
    ETH_InitStructure.ETH_LoopbackMode = ETH_LoopbackMode_Disable;                    //不启用自循环模式
    ETH_InitStructure.ETH_Mode = ETH_Mode_FullDuplex;                                 //全双工模式
  
    /*自动填充/CRC剥离处理不执行，转发所有帧*/
    ETH_InitStructure.ETH_AutomaticPadCRCStrip = ETH_AutomaticPadCRCStrip_Disable;   
#if CHECKSUM_BY_HARDWARE
  　ETH_InitStructure.ETH_ChecksumOffload = ETH_ChecksumOffload_Enable; //IPV4头文件硬件校验
#endif

    /*------------------------ ETH_MACFFR----------------------------------*/
  　ETH_InitStructure.ETH_ReceiveAll = ETH_ReceiveAll_Disable;                                   //MAC过滤只接受通过源目的地址的数据
    ETH_InitStructure.ETH_SourceAddrFilter = ETH_SourceAddrFilter_Normal_Enable;                 //MAC过滤源地址错误帧？
    ETH_InitStructure.ETH_PassControlFrames = ETH_PassControlFrames_BlockAll;                    //MAC不转发任何控制帧
    ETH_InitStructure.ETH_BroadcastFramesReception = ETH_BroadcastFramesReception_Enable;        //接收广播帧
    ETH_InitStructure.ETH_DestinationAddrFilter = ETH_DestinationAddrFilter_Normal;              //目的地址过滤结果正常
    ETH_InitStructure.ETH_PromiscuousMode = ETH_PromiscuousMode_Disable;                         //混杂模式，启用帧过滤
    ETH_InitStructure.ETH_MulticastFramesFilter = ETH_MulticastFramesFilter_Perfect;             //过滤器正常工作，不传送控制帧
    ETH_InitStructure.ETH_UnicastFramesFilter = ETH_UnicastFramesFilter_Perfect;                 //单播帧目的地址完美过滤

   /*------------------------   DMA  ETH_DMAOMR -----------------------------------*/  
   /* When we use the Checksum offload feature, we need to enable the Store and Forward mode: 
   the store and forward guarantee that a whole frame is stored in the FIFO, so the MAC can insert/verify the checksum, 
   if the checksum is OK the DMA can handle the frame otherwise the frame is dropped */
    /*丢弃校验错误帧不执行(因为未进行硬件校验)*/
    ETH_InitStructure.ETH_DropTCPIPChecksumErrorFrame = ETH_DropTCPIPChecksumErrorFrame_Disable;
    ETH_InitStructure.ETH_ReceiveStoreForward = ETH_ReceiveStoreForward_Disable;              //接收数据超过阈值转发
    ETH_InitStructure.ETH_FlushReceivedFrame = ETH_FlushReceivedFrame_Enable;                 //描述符被占用和接收FIFO不可用时清空FIFO(解决堵塞)
    ETH_InitStructure.ETH_TransmitStoreForward = ETH_TransmitStoreForward_Disable;            //发送数据完整帧转发
    ETH_InitStructure.ETH_TransmitThresholdControl = ETH_TransmitThresholdControl_64Bytes;    //发送阈值为64Bytes
    ETH_InitStructure.ETH_ForwardErrorFrames = ETH_ForwardErrorFrames_Disable;                //接收FIFO丢弃所有错误帧
    
    /*接收FIFO上传长度不够的好帧*/
　　ETH_InitStructure.ETH_ForwardUndersizedGoodFrames = ETH_ForwardUndersizedGoodFrames_Enable;  
　　ETH_InitStructure.ETH_ReceiveThresholdControl = ETH_ReceiveThresholdControl_64Bytes;       //接收阈值为64Bytes
    ETH_InitStructure.ETH_SecondFrameOperate = ETH_SecondFrameOperate_Enable;                  //DMA直接发送第二个帧，不需要之前帧回复
    
    /*------------------------   DMA  ETH_DMABMR -----------------------------------*/      
    ETH_InitStructure.ETH_AddressAlignedBeats = ETH_AddressAlignedBeats_Enable;                //传输地址对齐
    ETH_InitStructure.ETH_FixedBurst = ETH_FixedBurst_Enable;                                  //固定的突发
    ETH_InitStructure.ETH_RxDMABurstLength = ETH_RxDMABurstLength_32Beat;                              
    ETH_InitStructure.ETH_TxDMABurstLength = ETH_TxDMABurstLength_32Beat;
    ETH_InitStructure.ETH_DMAArbitration = ETH_DMAArbitration_RoundRobin_RxTx_2_1;             //发送和接收比例(上传数据时重要) 2:1
  
    /* Configure Ethernet */
    ETH_Init(&ETH_InitStructure, DP83848_PHY_ADDRESS);

    /* Enable the Ethernet Rx Interrupt  仅开启接收中断*/
    ETH_DMAITConfig(ETH_DMA_IT_NIS | ETH_DMA_IT_R, ENABLE);