Update README.md

Author: Bilchreis

README.md

@@ -17,6 +17,23 @@ Before first compiling the project in Microchip Studio the submodule of the avr-
 git submodule update --init
 ```
 
+### Build configurations:
+
+Buildconfigurations have the following Format:
+```'DisplayType'-'NetworkInterface'```
+
+| Display Type | Description                                            |
+|--------------|--------------------------------------------------------|
+| GCM_old_disp | old bw LCD display with low resolution                 |
+| ili9341      | Newer 2.2" rgb Display with a resolution of 240x320px  |
+
+| Network Interface | Description                                                                                             |
+|-------------------|---------------------------------------------------------------------------------------------------------|
+| XBEE              | Gascounter-module communicates via an xbee module with the server                                       |
+| LAN               | Gascountermodule emulates an Xbee module and sends messages directly over Ethernet via an X-Port Module |
+
+
+
 
 For further Information please refer to the [Wiki](https://github.com/SampleEnvironment/gascounter-module/wiki) pages