matlab访问串口的程序，包括：打开、关闭和清除串口对象；读串口、写串口；串口的IGNexiU数据流控制；还包括：怎么用matlab发送手机短信的mmurRqF例程；这是学习matlab访问系统硬件的原理。-Matlab serial access program, including: open, close, and clear the serial port object reading the serial port, serial port write serial IGNexi