circuit of the led adapted for different boards (#15)

* Update knx_facade.cpp

* Update knx_facade.h

* Update knx-demo.ino

examples/knx-demo/knx-demo.ino

@@ -1,5 +1,8 @@
 #include <knx.h>
 
+#ifdef ARDUINO_ARCH_ESP8266
+#include <WiFiManager.h>
+#endif
 
 // create named references for easy access to group objects
 #define goCurrent knx.getGroupObject(1)
@@ -55,6 +58,11 @@ void setup()
     SerialDBG.begin(115200);
 
     randomSeed(millis());
+	
+    #ifdef ARDUINO_ARCH_ESP8266
+    WiFiManager wifiManager;    
+    wifiManager.autoConnect("knx-demo");
+    #endif
 
     // read adress table, association table, groupobject table and parameters from eeprom
     knx.readMemory();
@@ -71,6 +79,17 @@ void setup()
         SerialDBG.print("Aenderung senden: "); SerialDBG.println(knx.paramByte(3));
         SerialDBG.print("Abgleich: "); SerialDBG.println(knx.paramByte(4));
     }
+	
+    #ifdef ARDUINO_ARCH_ESP8266
+    // GPIO (?) of the ESP8266, in which case this is determined by the board selection
+    knx.ledPin(LED_BUILTIN);
+    // GPIO (?) of the ESP8266, the value depends on the circuit used on the board of the led
+    //                          if "0" or "low" then the output switches to gnd, at "1" or "high" the output switches to vcc
+    //                          if the next line is commented out then the default is: output switches to gnd
+    //knx.ledPinActiveOn(HIGH);
+    // GPIO (14) of the ESP8266, in which case it is the connector pin D5 on WeMos D1 R2
+    knx.buttonPin(14);
+    #endif
 
     // start the framework. Will get wifi first.
     knx.start();