The Design On VGA Interface Based On ARM Linux System

The concept of embedded system began to appear in the 1970s. As the rapid development of semiconductor technology, microelectronics and information technology in the past 10 years, however, embedded system has been widely applied. Being different from desktop computer, the embedded system, which has the characteristics of low-cost, low power, small size, high performance, high reliability and configurable hardware and software, is specially designed for specific demands.With the development of technology and the expansion of demands, the traditional embedded monitor, which is less than 10-inch, severely limits the development of embedded system. At present, LCD display and interface standards of embedded system are not unified, which makes system maintenance and monitor upgrade difficult. The display interface of VGA is standard, wide-ranging in the market, technology mature and is widely used at present. Represented by Linux, embedded operating system brings the visual and graphic display interface, which is composed of windows and menus, into the realm of embedded system. It also takes the place of professional command language and promotes wider application of embedded system in enterprise solutions, industrial control and consumption product. In the time of embedded system and Internet, researching the VGA interface of embedded Linux system which is based on ARM framework, contributes to human-computer interaction, so that it applies widely and deep in the field of industry and life.In this paper, based on the characteristics of embedded system and VGA interface, the writer combined them together to research and achieved VGA interface design for embedded Linux systems. The concrete processes are as follows:(1) Based on the characteristics of ARMSYS2440 embedded development system and the S3C2440 microprocessor, the Linux operating system kernel is cut and transplanted into ARMSYS2440 development board.(2) By detailed analysis of VGA display standard and the principle of LCD controller of embedded system, and according to the VGA’s feature of replacing digital signal by analog signal, the D/A converter circuit module is constructed with ADV7123 chip as its core components. (3) Combined with Display timing of VGA interface, the display drive of Linux operating system kernel, which is based on framebuffer framework, is analyzed and modified by C language programing, so the output of display data fits for D/A converter and the output of display timing fits for VGA display timing.The main content of the research is part of AIS/GNSS shipboard navigation equipment key technology and system development(2012BAH36B02) which is National Surporting Plan Issue undertaken by Navigation Research Institute. The achievement of the research is applied in the display system of the equipment.