added examples to manage the file writing and readings

Author: Rocketct

examples/FileRead/FileRead.ino

@@ -0,0 +1,79 @@
+/*
+  Portenta - FileRead
+
+  The sketch shows how to mount an usb storage device and how to
+  read from an existing file.
+  to use this sketch create a .txt file named Arduino.txt,
+  in your storage device and write some content inside.
+  
+  The circuit:
+   - Portenta H7
+    
+  This example code is in the public domain.
+*/
+#include "USBHostMbed5.h"
+#include "USBHostMSD/USBHostMSD.h"
+#include "USBHostHub/USBHostHub.h"
+#include "USBHostSerial/USBHostSerial.h"
+#include "DigitalOut.h"
+#include "FATFileSystem.h"
+
+USBHostMSD msd;
+mbed::FATFileSystem fs("fs");
+
+mbed::DigitalOut pin5(PC_6, 0);
+
+// If you are using a Portenta Machine Control uncomment the following line
+//mbed::DigitalOut otg(PB_8, 1);
+ 
+#define BUFFER_MAX_LEN 64
+void setup() {
+  Serial.begin(115200);
+  while (!Serial);
+
+  // if you are using a Max Carrier uncomment the following line
+  //start_hub();
+
+  while (!msd.connect()) {
+    //while (!port.connected()) {
+    delay(1000);
+  }
+
+  Serial.println("Mounting USB device...");
+  int err =  fs.mount(&msd);
+  if (err) {
+    Serial.print("Error mounting USB device ");
+    Serial.println(err);
+    while (1);
+  }
+  Serial.print("read done ");
+  mbed::fs_file_t file;
+  struct dirent *ent;
+  int dirIndex = 0;
+  int res = 0;
+  Serial.println("Open file..");
+  FILE *f = fopen("/fs/Arduino.txt", "r+");
+  char buf[2];
+  Serial.println("File conntet:");
+
+  while (fgets(buf, 2, f) != NULL) {
+    Serial.println(buf);
+  }
+
+  Serial.println("File closing");
+  fflush(stdout);
+  err = fclose(f);
+  if (err < 0) {
+    Serial.print("fclose error:");
+    Serial.print(strerror(errno));
+    Serial.print(" (");
+    Serial.print(-errno);
+    Serial.print(")");
+  } else {
+    Serial.println("File closed");
+  }
+}
+
+void loop() {
+
+}

examples/FileWrite/FileWrite.ino

@@ -0,0 +1,66 @@
+#include "USBHostMbed5.h"
+#include "USBHostMSD/USBHostMSD.h"
+#include "USBHostHub/USBHostHub.h"
+#include "USBHostSerial/USBHostSerial.h"
+#include "DigitalOut.h"
+#include "FATFileSystem.h"
+
+USBHostMSD msd;
+mbed::FATFileSystem fs("fs");
+
+mbed::DigitalOut pin5(PC_6, 0);
+mbed::DigitalOut otg(PB_8, 1);
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial);
+  msd.connect();
+
+  while (!msd.connected()) {
+    //while (!port.connected()) {
+    delay(1000);
+  }
+
+  Serial.println("Mounting USB device...");
+  int err =  fs.mount(&msd);
+  if (err) {
+    Serial.print("Error mounting USB device ");
+    Serial.println(err);
+    while (1);
+  }
+  Serial.print("read done ");
+  mbed::fs_file_t file;
+  struct dirent *ent;
+  int dirIndex = 0;
+  int res = 0;
+  Serial.println("Open /fs/numbers.txt");
+  FILE *f = fopen("/fs/numbers.txt", "w+");
+  for (int i = 0; i < 10; i++) {
+    Serial.print("Writing numbers (");
+    Serial.print(i);
+    Serial.println("/10)");
+    fflush(stdout);
+    err = fprintf(f, "%d\n", i);
+    if (err < 0) {
+      Serial.println("Fail :(");
+      error("error: %s (%d)\n", strerror(errno), -errno);
+    }
+  }
+
+  Serial.println("File closing");
+  fflush(stdout);
+  err = fclose(f);
+  if (err < 0) {
+    Serial.print("fclose error:");
+    Serial.print(strerror(errno));
+    Serial.print(" (");
+    Serial.print(-errno);
+    Serial.print(")");
+  } else {
+    Serial.println("File closed");
+  }
+}
+
+void loop() {
+
+}