Add example arduino program.

arduino/serial_test.ino

@@ -0,0 +1,43 @@
+/* Copyright 2012 Google Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ *
+ * Project home page: http://code.google.com/p/usb-serial-for-android/
+ */
+
+// Sample Arduino sketch for use with usb-serial-for-android.
+// Prints an ever-increasing counter, and writes back anything
+// it receives.
+
+static int counter = 0;
+void setup() {
+  Serial.begin(115200);
+}
+
+void loop() {
+  Serial.print("Tick #");
+  Serial.print(counter++, DEC);
+  Serial.print("\n");
+
+  if (Serial.peek() != -1) {
+    Serial.print("Read: ");
+    do {
+      Serial.print((char) Serial.read());
+    } while (Serial.peek() != -1);
+    Serial.print("\n");
+  }
+  delay(1000);
+}