| The Video Monitoring (VM) is a vitally important part for a Security System. Digital VM based on computer technology and image/video compression has being used widely, as well as mini-digital products have being prevailed. Embedded VM products applying network technique are taking places with traditional systems. This thesis derives from an Embedded Video Sever project in Sichuan WiseSoft Co.,Ltd. It concerns the key aspects of transmission system of it. The system caters for basic needs in practicality and performs good co-operation with related units. It also lays a foundation for subsequent development.This thesis presents the following contents in sequence: In the first part, the whole architecture and position of the system was interpretted, which transmits compressed video data from front module to LAN. Then, it introduces the Microcontroller (MCU) used in the system based on ARM processor. Finally, it depicts concisely hardware and software developing flow and debugging method.The core hardware of system for controlling and transmission is the MCU. In addition, peripheral HW circuit and other resources are deployed. For debugging and networking transmission consideration, several interfaces are designed to make it convenient for communicating with outside. The system employs a Fast Ethernet Physical Layer Chip and EMAC embedded in MCU to support network transmission.The boot strategy of an embedded system should fit for its peculiar HW and specific application. Combined the memory characteristic of MCU and debugging needs in developing process, besides the normal work, a sub-level bootloader was designed. It satisfied with both boot modes to load next level program and communicate with PC using serial port. It's implement was provided in detail. Furthermore, the next level boot program which can load Linux OS was discussed.The netwrk device driver is a heavily part of SW. This thesis gives a thorough explanation of how the EMAC and PHY chip implement the network transmission. |
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