Added Platformio support

- firmware can now be built in Platformio too
- minor bug fixes
- added LED board picture

platformio.ini

@@ -0,0 +1,69 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+
+[platformio]
+include_dir = Inc
+src_dir     = Src
+
+;=================== VARIANT SELECTION ==========================
+;default_envs = VARIANT_DEBUG         ; DEFAULT Variant
+;default_envs = VARIANT_HOVERBOARD    ; HOVERBOARD Variant
+;================================================================
+
+;================================================================
+
+[env:VARIANT_DEBUG]
+platform        = ststm32
+board           = gd32f130c6
+debug_tool      = stlink
+upload_protocol = stlink
+framework       = spl
+extra_scripts   = add_nanolib.py        ; adds nanolib to reduce printf memory foot print
+
+
+; Serial Port settings (make sure the COM port is correct)
+monitor_port    = COM5
+monitor_speed   = 38400
+
+build_flags =
+    -IInc
+    -ISrc 
+    -DUSE_STDPERIPH_DRIVER
+    -DGD32F130_150
+    -Wl,-T./GD32F130C6T_FLASH.ld
+    -Wl,-lc
+    -Wl,-lm
+    -g -ggdb
+    -D VARIANT_DEBUG
+
+;================================================================
+
+[env:VARIANT_HOVERBOARD]
+platform        = ststm32
+board           = gd32f130c6
+debug_tool      = stlink
+upload_protocol = stlink
+framework       = spl
+extra_scripts   = add_nanolib.py
+
+build_flags =
+    -IInc
+    -ISrc 
+    -DUSE_STDPERIPH_DRIVER
+    -DGD32F130_150
+    -Wl,-T./GD32F130C6T_FLASH.ld
+    -Wl,-lc
+    -Wl,-lm
+    -g -ggdb
+    -D VARIANT_HOVERBOARD
+
+;================================================================
+