added fatfs example

FatFS.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h> //for va_list var arg functions
+
+/* USER CODE BEGIN PFP */
+void myprintf(const char *fmt, ...);
+/* USER CODE END PFP */
+
+/* Private user code ---------------------------------------------------------*/
+/* USER CODE BEGIN 0 */
+void myprintf(const char *fmt, ...) {
+  static char buffer[256];
+  va_list args;
+  va_start(args, fmt);
+  vsnprintf(buffer, sizeof(buffer), fmt, args);
+  va_end(args);
+
+  int len = strlen(buffer);
+  HAL_UART_Transmit(&huart3, (uint8_t*)buffer, len, -1);
+
+}
+/* USER CODE END 0 */
+
+/* USER CODE BEGIN 2 */
+  myprintf("\r\n~ SD card demo by kiwih ~\r\n\r\n");
+
+  HAL_Delay(1000); //a short delay is important to let the SD card settle
+
+  //some variables for FatFs
+  FATFS FatFs; 	//Fatfs handle
+  FIL fil; 		//File handle
+  FRESULT fres; //Result after operations
+
+  //Open the file system
+  fres = f_mount(&FatFs, "", 1); //1=mount now
+  if (fres != FR_OK) {
+	myprintf("f_mount error (%i)\r\n", fres);
+	while(1);
+  }
+
+  //Let's get some statistics from the SD card
+  DWORD free_clusters, free_sectors, total_sectors;
+
+  FATFS* getFreeFs;
+
+  fres = f_getfree("", &free_clusters, &getFreeFs);
+  if (fres != FR_OK) {
+	myprintf("f_getfree error (%i)\r\n", fres);
+	while(1);
+  }
+
+  //Formula comes from ChaN's documentation
+  total_sectors = (getFreeFs->n_fatent - 2) * getFreeFs->csize;
+  free_sectors = free_clusters * getFreeFs->csize;
+
+  myprintf("SD card stats:\r\n%10lu KiB total drive space.\r\n%10lu KiB available.\r\n", total_sectors / 2, free_sectors / 2);
+
+  //Now let's try to open file "test.txt"
+  fres = f_open(&fil, "test.txt", FA_READ);
+  if (fres != FR_OK) {
+	myprintf("f_open error (%i)\r\n");
+	while(1);
+  }
+  myprintf("I was able to open 'test.txt' for read!\r\n");
+
+  //f_puts("Obiwan: Hello there!\n", &fil);
+  //f_puts("Villain: Obiwan Kenobi\n", &fil);
+
+  //Read 30 bytes from "test.txt" on the SD card
+  BYTE readBuf[30];
+
+  //We can either use f_read OR f_gets to get data out of files
+  //f_gets is a wrapper on f_read that does some string formatting for us
+  TCHAR* rres = f_gets((TCHAR*)readBuf, 30, &fil);
+  if(rres != 0) {
+	myprintf("Read string from 'test.txt' contents: %s\r\n", readBuf);
+  } else {
+	myprintf("f_gets error (%i)\r\n", fres);
+  }
+
+  //Be a tidy kiwi - don't forget to close your file!
+  f_close(&fil);
+
+  //Now let's try and write a file "write.txt"
+  fres = f_open(&fil, "write.txt", FA_WRITE | FA_OPEN_ALWAYS | FA_CREATE_ALWAYS);
+  if(fres == FR_OK) {
+	myprintf("I was able to open 'write.txt' for writing\r\n");
+  } else {
+	myprintf("f_open error (%i)\r\n", fres);
+  }
+
+  //Copy in a string
+  strncpy((char*)readBuf, "a new file is made!", 19);
+  UINT bytesWrote;
+  fres = f_write(&fil, readBuf, 19, &bytesWrote);
+  if(fres == FR_OK) {
+	myprintf("Wrote %i bytes to 'write.txt'!\r\n", bytesWrote);
+  } else {
+	myprintf("f_write error (%i)\r\n");
+  }
+
+  //Be a tidy kiwi - don't forget to close your file!
+  f_close(&fil);
+
+  //We're done, so de-mount the drive
+  f_mount(NULL, "", 0);
+  /* USER CODE END 2 */