I have a project that was build for the FX2LP in Keil uVision C51, and now I am trying to build, compile and use that same program on the FX3. I have followed all the online instructions for the MDK-ARM plugin, and need to know if there are more things I am missing. I'm sure there are, however if there are libraries, configuration settings, possibly using MinGW or PATH changes? Any help would be amazing.
You cannot program an FX2lp project on to FX3. FX3 has separate development environment and tools. You need to have FX3 SDK.
This would be handy: