Added support for writing text (with example)

examples/tm1638_scrolling_modules_example/tm1638_scrolling_modules_example.pde

@@ -0,0 +1,56 @@
+/*
+TM1638.h - Library for TM1638.
+
+Copyright (C) 2011 Ricardo Batista <rjbatista at gmail dot com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the version 3 GNU General Public License as
+published by the Free Software Foundation.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <TM1638.h>
+
+#define MODULES 4
+
+// define a modules
+TM1638 modules[] = {
+	TM1638(3, 2, 4),
+	TM1638(3, 2, 5),
+	TM1638(3, 2, 6),
+	TM1638(3, 2, 7)
+};
+
+void setup() {
+}
+
+const char string[] = "       SEE LIBRARY PROJECT AT CODE.GOOGLE.COM        ";
+int base = 0;
+
+void loop() {
+  for (int i = 0; i < MODULES; i++) {
+    const char* pos = string + base + (i * 8);
+
+    if (pos >= string && pos + 8 < string + sizeof(string)) {
+      modules[i].setDisplayToString(pos);
+    } else {
+      modules[i].clearDisplay();
+    }
+  }
+
+  base++;
+
+  if (base == sizeof(string) - 8) {
+    base = -MODULES * 8;
+  }
+
+  delay(100);
+}
+