这个程序通过给ARM开发板的串口发送AT指令，使GPRSM模块可以在开发板上发短信，改程序用来控制GPRS模块自动发短信-This procedure to the ARM development board through the serial port to send AT commands, so that GPRSM in the development of on-board module can send text messages, changing the procedures used to control the GPRS module automatically send text messages