This is the source code of an old project of mine: a little DMX-Controller for up to 5 RGB-LED lamps.
As the TI lm3s is rather unavailable these days, I provide the code just to be able to follow my livestreams on youtube:
https://www.youtube.com/watch?v=KD9DUVACdQs&list=PLd79x-uW4uybzsgHmfreyOK2RCOY3pu1R
I will port the code to an STM32 some day so you can replicate the whole project.