Update TestSDCARD example

libraries/Portenta_SDCARD/examples/TestSDCARD/TestSDCARD.ino

@@ -1,36 +1,59 @@
+/*
+  Portenta - TestSDCARD
+
+  The sketch shows how to mount an SDCARD and list its content.
+
+  The circuit:
+   - Portenta H7 + Vision Shield
+   - Portenta H7 + Portenta Breakout
+
+  This example code is in the public domain.
+*/
 #include "SDMMCBlockDevice.h"
 #include "FATFileSystem.h"
 
 SDMMCBlockDevice block_device;
 mbed::FATFileSystem fs("fs");
 
 void setup() {
-  // put your setup code here, to run once:
-  delay(2000);
+  Serial.begin(9600);
+  while (!Serial);
+
+  Serial.println("Mounting SDCARD...");
   int err =  fs.mount(&block_device);
   if (err) {
     // Reformat if we can't mount the filesystem
     // this should only happen on the first boot
-    printf("No filesystem found, formatting... ");
-    fflush(stdout);
+    Serial.println("No filesystem found, formatting... ");
     err = fs.reformat(&block_device);
   }
+  if (err) {
+     Serial.println("Error formatting SDCARD ");
+     while(1);
+  }
+
   DIR *dir;
   struct dirent *ent;
-  printf("try to open dir\n");
+  int dirIndex = 0;
+
+  Serial.println("List SDCARD content: ");
   if ((dir = opendir("/fs")) != NULL) {
-    /* print all the files and directories within directory */
+    // Print all the files and directories within directory (not recursively)
     while ((ent = readdir (dir)) != NULL) {
-      printf ("%s\n", ent->d_name);
+      Serial.println(ent->d_name);
+      dirIndex++;
     }
     closedir (dir);
   } else {
-    /* could not open directory */
-    printf ("error\n");
+    // Could not open directory
+    Serial.println("Error opening SDCARD\n");
+    while(1);
+  }
+  if(dirIndex == 0) {
+    Serial.println("Empty SDCARD");
   }
 }
 
 void loop() {
-  // put your main code here, to run repeatedly:
-
+  // Empty
 }