例程讲解"/>
STM32F4X SDIO(六) 例程讲解
STM32F4X SDIO（六） 例程讲解-SD_PowerON
- 例程讲解-SD_PowerON
- SDIO引脚初始化和时钟初始化
- SDIO初始化(单线模式)
- CMD0:GO_IDLE_STATE
- 命令发送程序
- 命令响应程序
- CMD8:SEND_IF_COND
- CMD8参数
- 命令发送程序
- 命令响应程序
- CMD55:APP_CMD
- CMD55命令参数
- 命令发送
- 命令响应
- ACMD41:SD_SEND_OP_COND
- ACMD41参数
- 命令发送
- 命令响应
- SD卡上电流程
- 野火电子SD卡上电程序
从本节开始将会结合实际的例程讲解SD卡使用，包括SDIO控制器初始化，SD卡初始化，SD卡擦除、SD卡读写等。本例程将会使用野火电子的STM32F407的SD卡读写例程进行讲解。
例程讲解-SD_PowerON
SD_PowerON函数主要是配置SDIO的引脚、询问SD卡的工作电压和配置SD卡时钟
SDIO引脚初始化和时钟初始化
在使用STM32F4X的SDIO控制器前，需要先初始化SDIO的GPIO引脚。
STM32F4X的SDIO需要用到6个引脚
- PC8:SDIO的数据线0引脚
- PC9:SDIO的数据线1引脚
- PC10:SDIO的数据线2引脚
- PC11:SDIO的数据线3引脚
- PC12:SDIO的时钟引脚
- PD12:SDIO的命令引脚
void SD_LowLevel_Init(void)
{GPIO_InitTypeDef GPIO_InitStructure;/* 使能GPIOC和GPIOD时钟 */RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOD, ENABLE);/* 将GPIOC8、GPIOC9、GPIOC10、GPIOC11、GPIOC12和GPIOD2 复用为SDIO */GPIO_PinAFConfig(GPIOC, GPIO_PinSource8, GPIO_AF_SDIO);GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_SDIO);GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SDIO);GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_SDIO);GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SDIO);GPIO_PinAFConfig(GPIOD, GPIO_PinSource2, GPIO_AF_SDIO);/* 配置GPIOC8、GPIOC9、GPIOC10、GPIOC11、GPIOC12和GPIOD2引脚属性 */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;GPIO_Init(GPIOC, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;GPIO_Init(GPIOC, &GPIO_InitStructure);/* 使能SDIO时钟 */RCC_APB2PeriphClockCmd(RCC_APB2Periph_SDIO, ENABLE);/*使能DMA时钟 */RCC_AHB1PeriphClockCmd(SD_SDIO_DMA_CLK, ENABLE);
}在SD_LowLevel_Init函数中做了SDIO引脚和时钟的初始化操作。
SDIO初始化(单线模式)
在SD卡刚上电的初始化的时候，默认的总线宽度为1位总线宽度，其通信频率在400KHz左右，所以在SD卡上电的时候，也需要配置SDIO的总线宽度和工作频率。
SDIO_InitStructure.SDIO_ClockDiv = SDIO_INIT_CLK_DIV; // SDIOCLK分频系数
SDIO_InitStructure.SDIO_ClockEdge = SDIO_ClockEdge_Rising; // SDIO_CK的采样模式
SDIO_InitStructure.SDIO_ClockBypass = SDIO_ClockBypass_Disable;// SDIO_CK的使能
SDIO_InitStructure.SDIO_ClockPowerSave = SDIO_ClockPowerSave_Disable;// SDIO_CK是否使用节能模式
SDIO_InitStructure.SDIO_BusWide = SDIO_BusWide_1b;// SDIO总线宽度
SDIO_InitStructure.SDIO_HardwareFlowControl = SDIO_HardwareFlowControl_Disable; // 是否使用硬件流控
SDIO_Init(&SDIO_InitStructure);
这里需要注意的SDIO_CK的频率计算
根据数据手册可以知道SDIO_CK的计算公式。STM32F4X的SDIOCLK的时钟频率是48MHz，SDIO_INIT_CLK_DIV值为0x76,那么SDIO_CK频率计算如下
SDIO_CK = SDIOCLK / (0x76 + 2) = 400KHz
刚好满足SD卡上电时的频率要求。
CMD0:GO_IDLE_STATE
SD卡初始化的第一步是发送CMD0命令复位SD卡，让SD卡进入IDLE状态。
命令发送程序
SDIO_CmdInitStructure.SDIO_Argument = 0x0; // 没有参数SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_GO_IDLE_STATE; // CMD0SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_No; // 没有响应SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No; // 不等待SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable; // 使能CPSM状态机SDIO_SendCommand(&SDIO_CmdInitStructure);errorstatus = CmdError(); // 判断错误状态
调用SDIO_SendCommand函数发送CMD0命令到SD卡
命令响应程序
发送完CMD0之后需要判断发送是否有误，由于CMD0没有响应数据，所以只需判断SDIO控制器状态即可
static SD_Error CmdError(void)
{SD_Error errorstatus = SD_OK;uint32_t timeout;timeout = SDIO_CMD0TIMEOUT; /*!< 10000 */while ((timeout > 0) && (SDIO_GetFlagStatus(SDIO_FLAG_CMDSENT) == RESET)){timeout--;}if (timeout == 0){errorstatus = SD_CMD_RSP_TIMEOUT;return(errorstatus);}/*!< Clear all the static flags */SDIO_ClearFlag(SDIO_STATIC_FLAGS);return(errorstatus);
}
CMD8:SEND_IF_COND
CMD8命令的作用有两个，分别是电压校验和扩展现有的命令和响应。
在SD卡进入IDLE模式后，下一步就是通过CMD8给SD卡发送电压校验命令。
CMD8参数
bit[39:8]是CMD8的参数。
- bit[39:20]:保留位，为0
- bit[19:16]:支持的电压范围，从表中可以知道这里我们写1
- bit[15:8]:根据手册，bit[15:8]要为0xAA。
所以CMD8的参数的输入参数就为0x1AA
命令发送程序
SDIO_CmdInitStructure.SDIO_Argument = SD_CHECK_PATTERN; // 参数，为0x1AASDIO_CmdInitStructure.SDIO_CmdIndex = SDIO_SEND_IF_COND; // 命令编号 CMD8SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_Short; // 短响应SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No; // 不等待SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable; // 使用CPSM状态机SDIO_SendCommand(&SDIO_CmdInitStructure);
命令响应程序
CMD8的响应类型是R7，如果SD卡接受提供的电压范围就会返回R7响应，否则不会返回R7响应。
/* 检查R7响应 */
static SD_Error CmdResp7Error(void)
{SD_Error errorstatus = SD_OK;uint32_t status;uint32_t timeout = SDIO_CMD0TIMEOUT;status = SDIO->STA;while (!(status & (SDIO_FLAG_CCRCFAIL | SDIO_FLAG_CMDREND | SDIO_FLAG_CTIMEOUT)) && (timeout > 0)){timeout--;status = SDIO->STA;}if ((timeout == 0) || (status & SDIO_FLAG_CTIMEOUT)){/*!< Card is not V2.0 complient or card does not support the set voltage range */errorstatus = SD_CMD_RSP_TIMEOUT;SDIO_ClearFlag(SDIO_FLAG_CTIMEOUT);return(errorstatus);}if (status & SDIO_FLAG_CMDREND){/*!< Card is SD V2.0 compliant */errorstatus = SD_OK;SDIO_ClearFlag(SDIO_FLAG_CMDREND);return(errorstatus);}return(errorstatus);
}
如何SD卡响应CMD8命令，则代表该SD卡为SD2.0以上的卡。
SDIO_CmdInitStructure.SDIO_Argument = SD_CHECK_PATTERN;SDIO_CmdInitStructure.SDIO_CmdIndex = SDIO_SEND_IF_COND;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 = CmdResp7Error();if (errorstatus == SD_OK){CardType = SDIO_STD_CAPACITY_SD_CARD_V2_0; /*!< SD Card 2.0 */SDType = SD_HIGH_CAPACITY;}
CMD55:APP_CMD
在主机发完CMD8命令后，如果SD卡响应CMD8命令，那么接下来主机就需要发送CMD55命令，告诉SD卡在CMD55命令后的是特殊应用命令
CMD55命令参数
- bit[31:16]:RCA,SD卡的地址，这里因为还没有获取到SD卡地址，所以设为0
- bit[15:0]:一般为0
命令发送
SDIO_CmdInitStructure.SDIO_Argument = 0x00; // CMD55参数SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_APP_CMD; // 命令索引 CMD55SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_Short; // 短响应SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No; // 不等待SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable; // CPSM状态机使能SDIO_SendCommand(&SDIO_CmdInitStructure);
命令响应
CMD55的命令响应是R1，R1命令会返回SD卡的状态，所以在判断R1响应时需要判断SD卡的状态是否正常。
R1响应返回的卡状态如下
static SD_Error CmdResp1Error(uint8_t cmd)
{SD_Error errorstatus = SD_OK;uint32_t status;uint32_t response_r1;status = SDIO->STA;/* 判断SDIO控制器状态 */while (!(status & (SDIO_FLAG_CCRCFAIL | SDIO_FLAG_CMDREND | SDIO_FLAG_CTIMEOUT))){status = SDIO->STA;}if (status & SDIO_FLAG_CTIMEOUT){errorstatus = SD_CMD_RSP_TIMEOUT;SDIO_ClearFlag(SDIO_FLAG_CTIMEOUT);return(errorstatus);}else if (status & SDIO_FLAG_CCRCFAIL){errorstatus = SD_CMD_CRC_FAIL;SDIO_ClearFlag(SDIO_FLAG_CCRCFAIL);return(errorstatus);}/*!< 命令号是否为发送的命令号 */if (SDIO_GetCommandResponse() != cmd){errorstatus = SD_ILLEGAL_CMD;return(errorstatus);}/*!< Clear all the static flags */SDIO_ClearFlag(SDIO_STATIC_FLAGS);/*!< 依次判断SD卡状态位 */response_r1 = SDIO_GetResponse(SDIO_RESP1);if ((response_r1 & SD_OCR_ERRORBITS) == SD_ALLZERO){return(errorstatus);}if (response_r1 & SD_OCR_ADDR_OUT_OF_RANGE){return(SD_ADDR_OUT_OF_RANGE);}if (response_r1 & SD_OCR_ADDR_MISALIGNED){return(SD_ADDR_MISALIGNED);}if (response_r1 & SD_OCR_BLOCK_LEN_ERR){return(SD_BLOCK_LEN_ERR);}if (response_r1 & SD_OCR_ERASE_SEQ_ERR){return(SD_ERASE_SEQ_ERR);}if (response_r1 & SD_OCR_BAD_ERASE_PARAM){return(SD_BAD_ERASE_PARAM);}if (response_r1 & SD_OCR_WRITE_PROT_VIOLATION){return(SD_WRITE_PROT_VIOLATION);}if (response_r1 & SD_OCR_LOCK_UNLOCK_FAILED){return(SD_LOCK_UNLOCK_FAILED);}if (response_r1 & SD_OCR_COM_CRC_FAILED){return(SD_COM_CRC_FAILED);}if (response_r1 & SD_OCR_ILLEGAL_CMD){return(SD_ILLEGAL_CMD);}if (response_r1 & SD_OCR_CARD_ECC_FAILED){return(SD_CARD_ECC_FAILED);}if (response_r1 & SD_OCR_CC_ERROR){return(SD_CC_ERROR);}if (response_r1 & SD_OCR_GENERAL_UNKNOWN_ERROR){return(SD_GENERAL_UNKNOWN_ERROR);}if (response_r1 & SD_OCR_STREAM_READ_UNDERRUN){return(SD_STREAM_READ_UNDERRUN);}if (response_r1 & SD_OCR_STREAM_WRITE_OVERRUN){return(SD_STREAM_WRITE_OVERRUN);}if (response_r1 & SD_OCR_CID_CSD_OVERWRIETE){return(SD_CID_CSD_OVERWRITE);}if (response_r1 & SD_OCR_WP_ERASE_SKIP){return(SD_WP_ERASE_SKIP);}if (response_r1 & SD_OCR_CARD_ECC_DISABLED){return(SD_CARD_ECC_DISABLED);}if (response_r1 & SD_OCR_ERASE_RESET){return(SD_ERASE_RESET);}if (response_r1 & SD_OCR_AKE_SEQ_ERROR){return(SD_AKE_SEQ_ERROR);}return(errorstatus);
}
例程中判断R1响应的步骤如下
- 先判断SDIO控制的状态是否有错
- 判断R1响应的命令号是否为CMD55
- 最后再根据R1响应的SD卡状态位依次进行判断
根据波形图可知，返回的SD卡状态位0x120，也就是bit5和bit8置1
ACMD41:SD_SEND_OP_COND
发送ACMD41的作用是告诉SD卡，主机是否支持大容量卡，并且判断SD卡是否上电完成。
ACMD41参数
ACMD41参数是根据SD卡的OCR寄存器进行定义，以下为OCR寄存器的定义表
在这里我们需要注意以下几个bit
- bit[30]：卡容量位，如果是高容量卡，设置为 1，如果是标准卡，设置为 0。
- bit[31]：卡上电状态位，这个状态位在卡的上电流程完成后设置
在程序中，我们需要将bit30和bit31都设置为1，卡的电压设置为3.2-3.3，也就是bit20为1，则AMCD41的输入参数就为0xC0100000
命令发送
SDIO_CmdInitStructure.SDIO_Argument = SD_VOLTAGE_WINDOW_SD | SDType; // 参数 0xC0100000SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_SD_APP_OP_COND; // 命令索引 ACMD41SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_Short; // 短响应SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No; // 不等待SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable; // CPSM状态机使能SDIO_SendCommand(&SDIO_CmdInitStructure);
命令响应
ACMD41的响应是R3响应
例程中需要判断R3响应的OCR寄存器中的bit[31]是否为1，如果不为1，则需要循环发送CMD55和ACMD41，一直等到OCR寄存器总bit31为1
while ((!validvoltage) && (count < SD_MAX_VOLT_TRIAL)){/*!< SEND CMD55 APP_CMD with RCA as 0 */SDIO_CmdInitStructure.SDIO_Argument = 0x00;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_APP_CMD;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_APP_CMD);if (errorstatus != SD_OK){return(errorstatus);}SDIO_CmdInitStructure.SDIO_Argument = SD_VOLTAGE_WINDOW_SD | SDType;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_SD_APP_OP_COND;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 = CmdResp3Error();if (errorstatus != SD_OK){return(errorstatus);}response = SDIO_GetResponse(SDIO_RESP1);validvoltage = (((response >> 31) == 1) ? 1 : 0); // 判断bit31是否为1，如果为1则代表SD卡上电完成count++;}if (count >= SD_MAX_VOLT_TRIAL){errorstatus = SD_INVALID_VOLTRANGE;return(errorstatus);}if (response &= SD_HIGH_CAPACITY){CardType = SDIO_HIGH_CAPACITY_SD_CARD;}
至此，SD卡上电部分就完成了，下面来简介梳理一下SD卡上电的流程
SD卡上电流程
- 初始化SDIO引脚和时钟
- 初始化SDIO控制器，设置总线宽度为1，SDIO_CK频率不高于400KHz
- 发生CMD0命令，让SD卡进入IDLE模式
- 发生CMD8命令，判断SD卡是否支持设置的电压范围
- 发送CMD55命令
- 发送ACMD41命令，并判断SD卡是否上电完成，如果没有上电完成就重复5和6步骤
- SD卡上电完成
野火电子SD卡上电程序
SD_Error SD_PowerON(void)
{__IO SD_Error errorstatus = SD_OK;uint32_t response = 0, count = 0, validvoltage = 0;uint32_t SDType = SD_STD_CAPACITY;/*!< Power ON Sequence -----------------------------------------------------*//*!< Configure the SDIO peripheral *//*!< SDIO_CK = SDIOCLK / (SDIO_INIT_CLK_DIV + 2) *//*!< on STM32F4xx devices, SDIOCLK is fixed to 48MHz *//*!< SDIO_CK for initialization should not exceed 400 KHz */ SDIO_InitStructure.SDIO_ClockDiv = SDIO_INIT_CLK_DIV;SDIO_InitStructure.SDIO_ClockEdge = SDIO_ClockEdge_Rising;SDIO_InitStructure.SDIO_ClockBypass = SDIO_ClockBypass_Disable;SDIO_InitStructure.SDIO_ClockPowerSave = SDIO_ClockPowerSave_Disable;SDIO_InitStructure.SDIO_BusWide = SDIO_BusWide_1b;SDIO_InitStructure.SDIO_HardwareFlowControl = SDIO_HardwareFlowControl_Disable;SDIO_Init(&SDIO_InitStructure);/*!< Set Power State to ON */SDIO_SetPowerState(SDIO_PowerState_ON);/*!< Enable SDIO Clock */SDIO_ClockCmd(ENABLE);/*!< CMD0: GO_IDLE_STATE ---------------------------------------------------*//*!< No CMD response required */SDIO_CmdInitStructure.SDIO_Argument = 0x0;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_GO_IDLE_STATE;SDIO_CmdInitStructure.SDIO_Response = SDIO_Response_No;SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No;SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable;SDIO_SendCommand(&SDIO_CmdInitStructure);errorstatus = CmdError();if (errorstatus != SD_OK){/*!< CMD Response TimeOut (wait for CMDSENT flag) */return(errorstatus);}/*!< CMD8: SEND_IF_COND ----------------------------------------------------*//*!< Send CMD8 to verify SD card interface operating condition *//*!< Argument: - [31:12]: Reserved (shall be set to '0')- [11:8]: Supply Voltage (VHS) 0x1 (Range: 2.7-3.6 V)- [7:0]: Check Pattern (recommended 0xAA) *//*!< CMD Response: R7 */SDIO_CmdInitStructure.SDIO_Argument = SD_CHECK_PATTERN;SDIO_CmdInitStructure.SDIO_CmdIndex = SDIO_SEND_IF_COND;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 = CmdResp7Error();if (errorstatus == SD_OK){CardType = SDIO_STD_CAPACITY_SD_CARD_V2_0; /*!< SD Card 2.0 */SDType = SD_HIGH_CAPACITY;}else{/*!< CMD55 */SDIO_CmdInitStructure.SDIO_Argument = 0x00;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_APP_CMD;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_APP_CMD);}/*!< CMD55 */SDIO_CmdInitStructure.SDIO_Argument = 0x00;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_APP_CMD;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_APP_CMD);/*!< If errorstatus is Command TimeOut, it is a MMC card *//*!< If errorstatus is SD_OK it is a SD card: SD card 2.0 (voltage range mismatch)or SD card 1.x */if (errorstatus == SD_OK){/*!< SD CARD *//*!< Send ACMD41 SD_APP_OP_COND with Argument 0x80100000 */while ((!validvoltage) && (count < SD_MAX_VOLT_TRIAL)){/*!< SEND CMD55 APP_CMD with RCA as 0 */SDIO_CmdInitStructure.SDIO_Argument = 0x00;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_APP_CMD;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_APP_CMD);if (errorstatus != SD_OK){return(errorstatus);}SDIO_CmdInitStructure.SDIO_Argument = SD_VOLTAGE_WINDOW_SD | SDType;SDIO_CmdInitStructure.SDIO_CmdIndex = SD_CMD_SD_APP_OP_COND;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 = CmdResp3Error();if (errorstatus != SD_OK){return(errorstatus);}response = SDIO_GetResponse(SDIO_RESP1);validvoltage = (((response >> 31) == 1) ? 1 : 0);count++;}if (count >= SD_MAX_VOLT_TRIAL){errorstatus = SD_INVALID_VOLTRANGE;return(errorstatus);}if (response &= SD_HIGH_CAPACITY){CardType = SDIO_HIGH_CAPACITY_SD_CARD;}}/*!< else MMC Card */return(errorstatus);
}
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