各位牛人，小弟最近做一个项目，会用到STM32F103VC的SDIO读SD卡，单块读成功速度可以达到1M，多块读却不行？

请求各位能给予指点，或者相关代码参考。谢谢

我用的是stm32_eval_sdio_sd.c 的4.5版，

* @file    stm32_eval_sdio_sd.c

* @author  MCD Application Team

* @version V4.5.0

* @date    07-March-2011

* @brief   This file provides a set of functions needed to manage the SDIO SD

*          Card memory mounted on STM32xx-EVAL board (refer to stm32_eval.h

*          to know about the boards supporting this memory).

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SD_Error SD_ReadMultiBlocks(uint8_t *readbuff, uint32_t ReadAddr, uint16_t BlockSize, uint32_t NumberOfBlocks)

{

SD_Error errorstatus = SD_OK;

TransferError = SD_OK;

TransferEnd = 0;

StopCondition = 1;

SDIO->DCTRL = 0x0;

if (CardType == SDIO_HIGH_CAPACITY_SD_CARD)

{

BlockSize = 512;

ReadAddr /= 512;

}

/*!< Set Block Size for Card */

SDIO_CmdInitStructure.SDIO_Argument = (uint32_t) BlockSize;

SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_SET_BLOCKLEN;

SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_Short;

SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No;

SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable;

SDIO_SendCommand(&SDIO_CmdInitStructure);

errorstatus = CmdResp1Error(SD_CMD_SET_BLOCKLEN);

if (SD_OK != errorstatus)

{

return(errorstatus);

}

SDIO_DataInitStructure.SDIO_DataTimeOut = SD_DATATIMEOUT;

SDIO_DataInitStructure.SDIO_DataLength = NumberOfBlocks * BlockSize;

SDIO_DataInitStructure.SDIO_DataBlockSize = (uint32_t) 9 << 4;

SDIO_DataInitStructure.SDIO_TransferDir = SDIO_TransferDir_ToSDIO;

SDIO_DataInitStructure.SDIO_TransferMode = SDIO_TransferMode_Block;

SDIO_DataInitStructure.SDIO_DPSM = SDIO_DPSM_Enable;

SDIO_DataConfig(&SDIO_DataInitStructure);

/*!< Send CMD18 READ_MULT_BLOCK with argument data address */

SDIO_CmdInitStructure.SDIO_Argument = (uint32_t)ReadAddr;

SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_READ_MULT_BLOCK;

SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_Short;

SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No;

SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable;

SDIO_SendCommand(&SDIO_CmdInitStructure);

errorstatus = CmdResp1Error(SD_CMD_READ_MULT_BLOCK);

if (errorstatus != SD_OK)

{

return(errorstatus);

}

SDIO_ITConfig(SDIO_IT_RXOVERR|SDIO_IT_DTIMEOUT|SDIO_IT_DCRCFAIL|SDIO_IT_DATAEND, ENABLE);

SDIO_DMACmd(ENABLE);

SD_LowLevel_DMA_RxConfig((uint32_t *)readbuff, (NumberOfBlocks * BlockSize));

errorstatus = SD_WaitReadOperation();                                     //121112    等待读操作完成

if (errorstatus != SD_OK)

{

return(errorstatus);

}

while(SD_GetStatus()!=SD_TRANSFER_OK);                            //121112

return(errorstatus);

}