之前一直沒有寫過部落格，也不知道如何開始，現在想記錄一下自己做過的事情，以後回看還能記得更快。那就以此為開始吧~~~

專案需要，要實現一個將資料寫入到SD卡中的小demo，查找了一些資料，最後終於實現，將具體實現方案記錄如下。

1.搭建Zynq硬體平臺，根據開發板及自己需要設定好DDR、PL時鐘、外設等，本實驗要選中SD0、UART1；

2.搭建好硬體平臺如下所示，生成bit檔案並匯出到SDK中。

3.建立Appliaction Project，選擇Helloworld就行。讀寫SD卡用到了xilffs庫，所以需要在bsp中新增xilffs庫，同時選中xilffs庫做如下修改配置。

在配置上，主要參考了這位博主：https://blog.csdn.net/pro_he/article/details/79937426#zedboard四嵌入式應用程式開發例項三寫入資料到sd卡txt檔案中。

4.先測試官方提供例程，找到Xilinx Vivado安裝目錄下的xilffs提供程式碼，按照版本選擇，我的是3.7，D:\Xilinx\SDK\2017.4\data\embeddedsw\lib\sw_services\xilffs_v3_7\examples，將example內容拷貝到helloworld.c中。

這裡面主要就是實現了向SD卡中寫資料，再讀出寫入的資料，最後做判斷比較兩者資料，比較簡單。但程式碼提供的是生成了一個Test.bin

將其用：%！xxd轉換後，可看出具體資料，寫入是沒有問題的。

5.如何將資料提取出來去使用呢？我用的是UltraEdit，開啟如下

選中所有資料，右鍵 ——> 十六進位制複製選定檢視（V），貼上到Test.c檔案中，然後刪除掉不需要的列就可以了。

 6.讀寫SD卡的程式碼如下：

/***************************** Include Files *********************************/

#include "xparameters.h"	/* SDK generated parameters */
#include "xsdps.h"		/* SD device driver */
#include "xil_printf.h"
#include "ff.h"
#include "xil_cache.h"
#include "xplatform_info.h"

/************************** Constant Definitions *****************************/


/**************************** Type Definitions *******************************/

/***************** Macros (Inline Functions) Definitions *********************/

/************************** Function Prototypes ******************************/
int FfsSdPolledExample(void);

/************************** Variable Definitions *****************************/
static FIL fil;		/* File object */
static FATFS fatfs;
/*
 * To test logical drive 0, FileName should be "0:/<File name>" or
 * "<file_name>". For logical drive 1, FileName should be "1:/<file_name>"
 */
static char FileName[32] = "Test.bin";
static char *SD_File;
u32 Platform;

#ifdef __ICCARM__
#pragma data_alignment = 32
u8 DestinationAddress[10*1024*1024];
u8 SourceAddress[10*1024*1024];
#pragma data_alignment = 4
#else
u8 DestinationAddress[10*1024*1024] __attribute__ ((aligned(32)));
u8 SourceAddress[10*1024*1024] __attribute__ ((aligned(32)));
#endif

#define TEST 7

/*****************************************************************************/
/**
*
* Main function to call the SD example.
*
* @param	None
*
* @return	XST_SUCCESS if successful, otherwise XST_FAILURE.
*
* @note		None
*
******************************************************************************/
int main(void)
{
	int Status;

	xil_printf("SD Polled File System Example Test \r\n");

	Status = FfsSdPolledExample();
	if (Status != XST_SUCCESS) {
		xil_printf("SD Polled File System Example Test failed \r\n");
		return XST_FAILURE;
	}

	xil_printf("Successfully ran SD Polled File System Example Test \r\n");

	return XST_SUCCESS;

}

/*****************************************************************************/
/**
*
* File system example using SD driver to write to and read from an SD card
* in polled mode. This example creates a new file on an
* SD card (which is previously formatted with FATFS), write data to the file
* and reads the same data back to verify.
*
* @param	None
*
* @return	XST_SUCCESS if successful, otherwise XST_FAILURE.
*
* @note		None
*
******************************************************************************/
int FfsSdPolledExample(void)
{
	FRESULT Res;
	UINT NumBytesRead;
	UINT NumBytesWritten;
	u32 BuffCnt;
	u32 FileSize = (8*1024*1024);
	/*
	 * To test logical drive 0, Path should be "0:/"
	 * For logical drive 1, Path should be "1:/"
	 */
	TCHAR *Path = "0:/";

	Platform = XGetPlatform_Info();
	if (Platform == XPLAT_ZYNQ_ULTRA_MP) {
		/*
		 * Since 8MB in Emulation Platform taking long time, reduced
		 * file size to 8KB.
		 */
		FileSize = 8*1024;
	}

	for(BuffCnt = 0; BuffCnt < FileSize; BuffCnt++){
		SourceAddress[BuffCnt] = TEST + BuffCnt;
	}

	/*
	 * Register volume work area, initialize device
	 */
	Res = f_mount(&fatfs, Path, 0);

	if (Res != FR_OK) {
		return XST_FAILURE;
	}

	/*
	 * Path - Path to logical driver, 0 - FDISK format.
	 * 0 - Cluster size is automatically determined based on Vol size.
	 */
	Res = f_mkfs(Path, 0, 0);
	if (Res != FR_OK) {
		return XST_FAILURE;
	}

	/*
	 * Open file with required permissions.
	 * Here - Creating new file with read/write permissions. .
	 * To open file with write permissions, file system should not
	 * be in Read Only mode.
	 */
	SD_File = (char *)FileName;

	Res = f_open(&fil, SD_File, FA_CREATE_ALWAYS | FA_WRITE | FA_READ);
	if (Res) {
		return XST_FAILURE;
	}

	/*
	 * Pointer to beginning of file .
	 */
	Res = f_lseek(&fil, 0);
	if (Res) {
		return XST_FAILURE;
	}

	/*
	 * Write data to file.
	 */
	Res = f_write(&fil, (const void*)SourceAddress, FileSize,
			&NumBytesWritten);
	if (Res) {
		return XST_FAILURE;
	}

	/*
	 * Pointer to beginning of file .
	 */
	Res = f_lseek(&fil, 0);
	if (Res) {
		return XST_FAILURE;
	}

	/*
	 * Read data from file.
	 */
	Res = f_read(&fil, (void*)DestinationAddress, FileSize,
			&NumBytesRead);
	if (Res) {
		return XST_FAILURE;
	}

	/*
	 * Data verification
	 */
	for(BuffCnt = 0; BuffCnt < FileSize; BuffCnt++){
		if(SourceAddress[BuffCnt] != DestinationAddress[BuffCnt]){
			return XST_FAILURE;
		}
	}

	/*
	 * Close file.
	 */
	Res = f_close(&fil);
	if (Res) {
		return XST_FAILURE;
	}

	return XST_SUCCESS;
}
 

最後根據自己的需要進行修改就行，我用到的是修改了SourceAddress[ ]的大小以及內容取值。

u8 SourceAddress[10*1024*1024];

for(BuffCnt = 0; BuffCnt < FileSize; BuffCnt++){
		SourceAddress[BuffCnt] = TEST + BuffCnt;
	}