STM32单片机IAP自编程启动程序。用户通过GPRS等途径向单片机发送新的程序，stm32通过本启动代码判断是否有程序升级，进入升级模式。本代码使用IAR FOR ARM编写，工程可直接使用。-STM32 MCU IAP since the start of the programming process. Users through GPRS and other ways to send a new program to the microcontroller, stm32 through