Finally I have finished port for TI's MCU Tiva TM4C1294. It took some time to learn how to program all necessary hardware. Photos of this prototype and all source files needed to run it are available on the project's web page.
In contrast with STM32 version, Tiva version contains support for UART gray-link only. I was too lazy to port USB to this MCU just for fun :-) All other parts are working the same way as on STM32 version.