Optimization of UART communication based on LEON2 hardware debug support unit

Researched on LEON2 hardware debug support unit, DSU communication link structure and communication protocol, we find out that the UART communication of LEON2 DSU does not check the communication data, which will cause problems when debugging on LEON2. So we offer an optimization design of UART communication based on LEON2 DSU by adding a parity bit to DSU UART data frame, and sending back the data written to DSU. Finally, users can effectively check the communication data, in order to speed up the debugging process.