Added support for LCD I2C Shield

Author: christian-kardach

Software/Arduino code/OpenAstroTracker/Configuration_adv.hpp

@@ -131,6 +131,15 @@
 #define HEADLESS_CLIENT 0
 #endif
 
+////////////////////////////
+//
+// ARDUINO RGB LCD SHIELD I2C
+// There are two different chips supported by the LiquidTWI2 library,
+// check the marking on your shield
+#define I2C_DISPLAY 0
+#define I2C_TYPE_MCP23008 0
+#define I2C_TYPE_MCP23017 1
+
 #ifdef __AVR_ATmega328P__   // UNO must use headless
 #undef HEADLESS_CLIENT
 #define HEADLESS_CLIENT 1

Software/Arduino code/OpenAstroTracker/platformio.ini

@@ -17,6 +17,7 @@ lib_deps =
 	teemuatlut/TMCStepper @ ^0.7.1
 	waspinator/AccelStepper @ ^1.61
 	arduino-libraries/LiquidCrystal @ ^1.0.7
+	lincomatic/LiquidTWI2@^1.2.7
 
 [env]
 framework = arduino