Design Of Embedded Gigabit Ethernet Camera Transmission System Based On FPGA

As a kind of optical measuring tools, Ultra fast framing camera has been widly applied in space, mapping, high-energy particle blasting experiment, industrial control.The theory of framing camera is using a plurality of cameras for the same goal, each camera generates a delay in ps scale. It can detect the continuous change of the target, and it has good effect in the instantaneous dynamic field, so it has great significance in scientific research. The amount of image data high-speed framing camera is very large, traditional interface technology is hard to meet the requirements of high resolution image transmission. This design adopts the Gigabit Ethernet interface technology to solve the problem of data transmission. Compared with the traditional interface technology, network transmission has strong anti-interference ability, quick transmission speed, and long transmission distance, etc.This design is based on the network transmission theory. According to networklayer by layer design scheme, using dedicated physical layer chip 88E1111 to implemente physical layer, using Gigabit Ethernet IP core to implemente data link layer, using embedded system to implemente network layer. Application layer is prepared on the PC machine. The physical layer and data link layer’s network interface is GMII. The design and implementation of an embedded system is in the Virtex-4 FPGA. In the process of system realization, hardware design includes the Virtex-4 FPGA DCM clock generating and realized the three state Ethernet IP kernel function. The software of the system in on the EDK XPS platform, using PowerPC405 processor, and transplanted into real-time operating system(RTOS) Vxworks, finished writing embedded software in Tornado.The innovation of this design is elaborated the key performance index of network-throughput has connection with IP core, processor performance and memory performance. Especially, analyzed the process in the operating system is in detail software connect with hardware through address mapping, and bus is in the system to access the hardware implementation code to combination of hardware and software of each module, bus access the network performance also has a relationship with the memory, the memory of the processor instruction andinteractive, interactive data and the IP kernel. The memory unit on the circuit board is SDRAM, the paper pointed out that using DDR2 or DDR3 can improve the network throughput. In the actual testing process, influence of network throughput and network card and PC terminal operating system, Linux operating system is more suitable for network transmission ratio than Windows system. Another characteristic of this paper is solidifying program, program is not directly written in block RAM by default, but loaded the start drive, the drive burned in the platform of flash, the application and test program writing in the CPLD flash. The execution of the application program from the start boot processor point to the application software when the driving power is turned on. So the code will not get lost when the circuit is powered off, but also solves the problem of insufficient capacity of the RAM. Finally, using Netperf network detection method to detect network throughput, using a program to verify the network transmission function, the two ways work together to ensure the correctness of the network design.