Embedded system with technical point of view and perspective can be divided into two ways, the technical point of view: with application as the center, on the basis of computer technology, software and hardware can be cut, the application system for function, reliability, cost and so on have specific requirements of special computer system, is the application, the operating system and computer hardware integrated system, the system Angle: an embedded system is designed to accomplish complex function of hardware and software, and make it tightly coupled together in a computer system, characteristics: limited power consumption, low cost, more speed, environment, system kernel is small, strong specificity, not monopoly, product stability, real time... Embedded system: software subsystem (including the application and operating system), the hardware subsystem (processors, peripherals (memory, the input interface, output interface) embedded system hardware and software framework: function (application) software layer (file system, A graphical user interface, task management, real-time operating system (RTOS)) middle tier BSP/HAL hardware abstraction layer/plate support board hardware layer (D/A, A/D, I/O), the embedded microcontroller processor, (common interface, ROM, STRAM), the human-computer interaction interface embedded computer system,