BF548串口驱动-自动波特率模式 范例通过串口接收来自PC的字符，然后将接收到的字符回发给pc，传输格式是8数据位，1停止位，没有校验位-UART Autobaud detect example for BF548 UART driver.The example receives characters over the UART from a PC communication program.The example receives characters from the PC and ech