The Hardware Design And Testing Of Visual And Embedded Access Control System Based On Network

With the ever-increasing residents,the management and security of residential community has become increasingly important.Visitor registration and porter on duty are not suitable for modern management requirements of speed, convenience, security any more.And the era when tenants need to go downstairs and open the door for visitors has long been out of.Therefore, the community is in urgent need of access control system which is safe, reliable, cost-effective and can be centrally managed.The visial and phonic access control system can complete the mission.As a convenient and secure tool,the visial and phonic access control system is welcomed by the majority of users.In this background,the topic is made for hardware design and debugging project of embedded and network-based visual access control system. The access control system for the current family can only transmit voice and can not satisfy the user's needs more and more.In this case,the goal of this project is to design a network access control system, which is visualization and ARM9-based chip S3C2440A.The system not only meets the needs of video, but also further strengthen the access security, provide electronic photo album, community management, information publishing function and so on, the significance is very important for use and realism.In order to achieve the function, which is embedded and network-based visualization S3C2440A Access Control System,the main research contents in this paper are as follows:(1) ARM embedded system theory and system identification.It mainly contains system architecture, hardware, electrical characteristics of based on S3C2440A visual embedded network access control system.(2) Circuit schematic diagram and PCB design technology.It mainly contains circuit design and PCB schematic drawing of S3C2440A-based visualization of the embedded network access control system using Protel DXP software.(3) The work based on S3C2440A and embedded network visual access control system's hardware debug and improvement.For the functions of the system and the main contents of this paper, it mainly carrys out the following steps:First of all, the embedded network access control system visualization scheme.According to the function of the system to achieve, that is, Web-based video intercom function,we have two options:The first is based on DSP and CPLD, high-speed system solutions,Second, ARM-based system solutions.Taking the economic and the universal application into account,the system selectes the second program as a template,that is based on the core S3C2440A chip ARM embedded system solutions.At the same time, the outer part of the whole system further to be divided into each functional module.They mainly include audio and video data acquisition module, data storage module, audio playback module, image display module and data network transmission module and so on.By comparing the specific optional chips of sub-modules,We selecte SDRAM memory chip HY57V561620 for dynamic data storage, FLASH memory chip K9F1208U0B for fixed data storage, CS8900A devices for network data transmission,UDA1341 for audio playback devices, USB camera for video capture device and a 5.6-inch LCD AT056TN52 for the display.Finally,we determine the system solution of the overall program and the concrete realization of the program modules.Secondly, the hardware schematic design of the S3C2440A-based network visual access control system.The system uses two SDRAM chips HY57V561620 to form parallel 32-bit data bus, using 4-byte aligned to achieve high-speed dynamic data access. The NAND FLASH chip K9F1208U0B which uses IO [7:0] as data, address and control signal line multiplexing is used to complete the fixed data access. audio chip UDA1341 which uses IIS interface to complete data transmission and L3 interface to complete control signal transmission is used to complete the AD/DA conversion. TFT LCD AT056TN52 which uses RGB interface completes the image display. Chip CS8900A which uses duplicate address line, data line with memory completes the network transmission of the data. These external devices work under the control of S3C2440A which is the core of the system. There are dedicated internal SDRAM controller, NAND FLASH controller, IIS audio interface and LCD controller inside S3C2440A which can achieve the various functions of the system successfully. under the premise of Understanding the various parts of the system and proficiency in software Protel DXP, We completed a system functional module schematic design and the overall integration.Then, The hardware PCB Design of S3C2440A-based network video access control system. Most of the chips selected in the system are SMD(Surface Mounted Devices) package, and even the complex BGA(Ball Grid Array) (17×17) package. In order to complete the complex wiring and provide a good anti-interference ability, The PCB design of this system separates the core board and motherboard. Core board design uses six panels.But in order to save costs,motherboard uses dual-panel design. At the same time, the system works in high-speed. Therefore, it will produce a series of problems which high-speed circuit may lead to, including reflection, crosstalk, electromagnetic radiation and so on. PCB design of the system takes full account of high-speed circuit design requirements. We have adopted reflection and crosstalk suppression measures, and stable operation of the hardware for the system to lay a good foundation. Finally, the circuit welding and hardware debugging of the S3C2440A-based network video access control system. After a few steps ahead, we realized the system programming, system schematic design and PCB board production.At last we need to test the stability and correctness of the hardware circuit module to verify the reliability of the hardware system. In order to protect the device and rule out errors easily, hardware debugging and circuit welding of each module need to be carried out step-by-step. First of all, we use a multimeter and oscillograph to detecte the correctness of the smallest system of S3C2440A. Then we Programe to achive characters input and output of the serial port, SDRAM data access, FLASH data access, audio recording and playback, data download and transmission by network as well as LCD display and so on. After testing, the modules of the system work correctly.At this point, the system design and hardware debugging based on the S3C2440A embedded network visual access control system has been successfully completed. After testing the hardware system can work steadily and can complete the design features successfully. After the design of this subject, I have a clear cognition about the ARM system hardware architecture, have a deep understanding about the working principle of the functional modules, accumulate a lot of experience in hardware design, Mastere hardware debugging approach of the ARM system. All of these lay the foundation for the future development of the similar system. In addition, the hardware system can be used not only as a network visual access control system, also applies to community services, information query and so on.Of course, due to the lack of design experience and a no-comprehensive consider, there are still many points that need to be improved in the hardware system, such as to further reduce electromagnetic radiation, to improve working methods and to enhance the work efficiency. At the same time, with the rapid development of embedded processor, embedded systems changes from a hardware-based into both hardware and software. And 32-bit embedded ARM processor needs operating systems to be brought into full play the potential for greater. Therefore, the development of embedded systems and applications have put forward higher requirements for us. However, only in full knowledge of system hardware resources, the designer can write a better program. Although this paper focuses on hardware design and debugging, with the full understanding and awareness of hardware design and hardware configuration,I will take this opportunity to walk into the hall of driven development and software design. This is to adapt to the needs of the development of the times.