test port for rs232,用PB9写的串口通讯测试程序，带有总线方式，可根据自己情况修改代码。-test for RS232 port with PB9 write the serial communications testing procedures with a bus, according to its own circumstances can modify the code.

test port for rs232,用PB9写的串口通讯测试程序，带有总线方式，可根据自己情况修改代码。-test for RS232 port with PB9 write the serial communications testing procedures with a bus, according to its own circumstances can modify the code.