| The combination of Internet and embedded system has become the trend of embedded system development in the future. The embedded system based on ARM has been applied widely in industry because of low consume, low cost and high performance.EPA (Ethernet for Plant Automation) device is the bottom device in field bus control system based on high speed Ethernet. To satisfy the real-time attribute in industry field and cooperate with other devices better, this paper introduces the core technic about ARM microprocessor, Linux operating system and designs a set of embedded system.Research of the paper includes the hardware design and software design. The embedded system is composed of AT91RM9200 microprocessor, 8M FLASH, 32M SDRAM and Ethernet interface, serial interface, in-out interface. According to the design rules of the microprocessor and other chips the hardware design includes power, crystal circuits, memorizer, Ethernet, serial and extending in-out interfaces. The Printed Circuit Board adopts four layers SMT technics, and by circuit debugging the hardware can run normally. Linux is loaded to the hardware. The thesis studies the system structure and workflow of Bootloader, and the start-up course of kernel, it also analyses the porting course of Linux from two aspects of Bootloader and kernel. The paper researches the device management of the Linux operating system and the strategy of interrupt management of the Linux device drivers. Through analyzing the developing methods and technologies of character device driver of Linux, the common process of developing character device driver was elicited, the developing frame of character device driver was put forward. The programs about the I/O device drivers are completed and make the system compatible to the EPA device.The EPA device based on embedded system can satisfy the real-time attribute in industry field and cooperate with other devices better. It makes the EPA device expand its functions easier. |
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