added Documentation

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

examples/SendOnButton/SendOnButton.ino

@@ -0,0 +1,39 @@
+/*
+ This sketch demonstrates, how to use the SoftRS485 library.
+ It listens on the RS485 network bus.
+ When the button is pressed, it sends some messages on the bus.
+ */
+
+#include <SoftRS485.h>
+
+#define BUTTON 7
+
+boolean state = LOW;
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println(F("This is ReceiveDemo, version 0.1"));
+  
+  init485(2,3,4,5); // library initialization:
+  // connect pin 2 to RO of Max485
+  // connect pin 3 to ^RE of Max485
+  // connect pin 4 to DE of Max485
+  // connect pin 5 to DI of Max485
+  pinMode(BUTTON,INPUT_PULLUP);
+}
+
+void loop(){
+  if (available485()) Serial.println("Received: "+get485message());
+  
+  boolean new_state = digitalRead(BUTTON);
+  if (new_state != state){
+    if (state){
+      for (int i=1; i<16; i++){
+        String s = "Button pressed   "+String(i);
+        send485(s.c_str());
+        delay(100);
+      }
+    } else send485("Button released!");
+    state = new_state;
+  }
+}