对于串口通讯，存在的解析乱码的问题

使用STM32串口的letter作为shell工具
编码为utf-8

可以发现，每次对于中文解析的都不一样

letter:/$ cmds

Command List:
fat CMD -------- FATFS测试
mount CMD -------- 挂载sd卡
unmount CMD -------- 取消挂���sd卡
ls CMD -------- 遍历���定目录
cat CMD -------- 文���读文件
setVar CMD -------- set var
help CMD -------- show command info
users CMD -------- list all user
cmds CMD -------- list all cmd
vars CMD -------- list all var
keys CMD -------- list all key
clear CMD -------- clear console

letter:/$ cmds

Command List:
fat CMD -------- FATFS测试
mount CMD -------- 挂载sd���
unmount CMD -------- ���消挂载sd卡
ls CMD -------- 遍历指���目录
cat CMD -------- 文本读文件
setVar CMD -------- set var
help CMD -------- show command info
users CMD -------- list all user
cmds CMD -------- list all cmd
vars CMD -------- list all var
keys CMD -------- list all key
clear CMD -------- clear console

当我使用VOFA+选择RawData模式时，会出现一样的上述问题，但是当我选择VOFA+的FireWater模式时，就不会出现上述问题，探查原因发现，FireWater模式以换行作为帧结束标志，所以遇到换行才会开启一帧的解析，可是我看了本项目的设置相关选项，并没有这样的设置，希望进行修复

Reproduce the issue with an STM32 serial connection using UTF-8 and compare VOFA+ RawData with FireWater mode. Inspect the serial frame parsing and related configuration options; done means Chinese output is decoded consistently and newline-based framing can be configured or otherwise handled correctly.

Written by the indexing model from the issue text.