灵动微课堂 (第193讲) | 使用MM32F3270的SDIO驱动SD卡

程序设计
根据 SD 卡识别过程和数据传输过程理解 SD 卡驱动函数代码。这部分代码内容也较多，在本文中只对部分核心函数介绍其功能，详细代码可到灵动官网下载参考。

SPIO配置初始化

void SDIO_ConfigInit(void)
{
SDIO_InitTypeDef SDIO_InitStruct;

SDIO_PIN_GPIO_Config();
SDIO_Detect_Pin_Config();

RCC_AHBPeriphClockCmd(RCC_AHBENR_SDIO, ENABLE);
SDIO_DeInit();
RCC_AHBPeriphClockCmd(RCC_AHBENR_SDIO, DISABLE);
RCC_AHBPeriphClockCmd(RCC_AHBENR_SDIO, ENABLE);

SDIO_ClockSet(0x2F);
SDIO_StructInit(&SDIO_InitStruct);

SDIO_InitStruct.SDIO_OPMSel = SDIO_MMC_CTRL_OPMSel;
SDIO_InitStruct.SDIO_SelPTSM = SDIO_MMC_CTRL_SelSM;
SDIO_InitStruct.SDIO_DATWT = SDIO_MMC_CTRL_DATWT;
SDIO_Init(&SDIO_InitStruct);

SDIO_CRCConfig(SDIO_MMC_CRCCTL_CMD_CRCEN | SDIO_MMC_CRCCTL_DAT_CRCEN, ENABLE);
}
void show_sdcard_info(void)
{
switch(SDCardInfo.CardType) {
case SDIO_STD_CAPACITY_SD_CARD_V1_1:
printf("Card Type:SDSC V1.1rn");
break;
case SDIO_STD_CAPACITY_SD_CARD_V2_0:
printf("Card Type:SDSC V2.0rn");
break;
case SDIO_HIGH_CAPACITY_SD_CARD:
printf("Card Type:SDHC V2.0rn");
break;
case SDIO_MULTIMEDIA_CARD:
printf("Card Type:MMC Cardrn");
break;
}
printf("Card ManufacturerID:%drn", SDCardInfo.SD_cid.ManufacturerID); //The manufacturer ID
printf("Card RCA:%drn", SDCardInfo.RCA); //Card relative address
printf("Card Capacity:%d MBrn", (u32)(SDCardInfo.CardCapacity >> 20));
printf("Card BlockSize:%drnrn", SDCardInfo.CardBlockSize);
}

SD卡的初始化主要进行卡识别和卡状态获取，定义SD_Init()如下：SD_Error SD_Init(void)
{
u32 clk;
RCC_ClocksTypeDef bclk;
u32 targetFreq;
__IO SD_Error errorstatus = SD_OK;
u8 clkdiv = 0;
INTX_DISABLE();


errorstatus = SD_PowerON(); //SD Power On
if (errorstatus != SD_OK) {
return errorstatus;
}
errorstatus = SD_InitializeCards(); //Initialize SD Card
if (errorstatus != SD_OK) {
return errorstatus;
}
errorstatus = SD_GetCardInfo(&SDCardInfo); //Get card information
if (errorstatus != SD_OK) {
return errorstatus;
}
errorstatus = SD_SelectDeselect((u32)(SDCardInfo.RCA << 16)); //Select the SD card
if (errorstatus != SD_OK) {
return errorstatus;
}
errorstatus = SD_EnableWideBusOperation(1); //4 bit width, if it is an MMC card, you cannot use 4 bit mode
if ((errorstatus != SD_OK)) {
if( (SDIO_MULTIMEDIA_CARD == CardType)) {
if (SDCardInfo.CardType == SDIO_STD_CAPACITY_SD_CARD_V1_1 || SDCardInfo.CardType == SDIO_STD_CAPACITY_SD_CARD_V2_0) {
clkdiv = 0; //V1.1/V2.0 card with the maximum setting of 48/4=12Mhz
}
else {
clkdiv = 1; //For other cards such as SDHC, the maximum setting is 48/2=24Mhz
}
if(clkdiv != 0) {
targetFreq = 24000000;

}
else {
targetFreq = 12000000;
}
RCC_GetClocksFreq(&bclk);
clk = (bclk.HCLK_Frequency / 2 / 2 / targetFreq - 1);
SDIO_ClockSet(clk);

}
else {
__NOP();
}
}
else {
if (SDCardInfo.CardType == SDIO_STD_CAPACITY_SD_CARD_V1_1 || SDCardInfo.CardType == SDIO_STD_CAPACITY_SD_CARD_V2_0) {
clkdiv = 0;
}
else {
clkdiv = 1;
}
if(clkdiv != 0) {
targetFreq = 24000000;

}
else {
targetFreq = 12000000;
}
RCC_GetClocksFreq(&bclk);
clk = (bclk.HCLK_Frequency / 2 / 2 / targetFreq - 1);
SDIO_ClockSet(clk);

}
INTX_ENABLE();
return errorstatus;
}

1)SD_PowerON()函数用于查询卡的工作电压和时钟控制配置，并返回 SD_Error 类型错误，该函数是整个 SD 识别的关键函数。
2)SD_InitializeCards()函数初始化SD卡，并将其置入就绪状态；
3)SD_GetCardInfo()函数获取SD卡的信息；
4)SD_SelectDeselect()选择SD卡，发送CMD7命令，选择具有相对地址(RCA)的卡作为ADDR；
5)SD_EnableWideBusOperation()配置SDIO数据宽度；
6)SDIO_ClockSet()配置SDIO的时钟频率。

获取SD卡信息及数据的函数定义如下：void read_sd_card_info(void)
{
u16 i = 5;
SD_Error result;
u32 sd_size;

SDIO_ConfigInit();
printf("SDCARD TESTrn");
while(1) {

result = SD_Init();

if(result == SD_OK) {
break;
}
printf("SD Card Error!rn");

DELAY_Ms(1);
}
show_sdcard_info();
i = 5;
while(i--) {
if(SD_ReadDisk(&vbuf[0], 0, 1) == 0) {
printf("UART Sending Data...rn");
printf("SECTOR 0 DATA:rn");
for(sd_size = 0; sd_size < 512; sd_size++) {
printf("%02x ", vbuf[sd_size]);
}
printf("rnDATA ENDEDrn");
printf("UART Send Data Over!rn");
}
DELAY_Ms(50);
}
}

实验演示
在MB-039开发板的SDIO/TF卡槽插入SD卡，运行程序，串口调试助手显示如下：
如果SD卡可用，串口调试助手会打印SD卡的信息，包括卡类型、生产ID、RCA、容量和块大小，接着打印扇区0的数据，会连续打印5次该部分内容。

本次实验的例程可以通过MindMotion的官网下载MM32F3270 lib_Samples：
https://www.mindmotion.com.cn/pr ... instream/mm32f3270/
工程路径如下：
~MM32F327x_Samples LibSamplesSDIOSDIO_ReadSDCardInfo
可以看到详细的样例与功能操作。