uart VHDL code : include tx,rx,parity bit control

该工程用verilog编写，已通过串口调试助手调试通过，接收模块采用8倍波特率采样数据，有较好的滤波功能，在PC上完成自发自收功能。-Verilog prepared by the project, has passed through the serial debug debugging assistant, receiving 8 times the baud rate module sampling data, a better filtering in the PC to complet