基于FPGA的在线可写CAM存储器设计

FPGA Based On-line Writable Content Addressable Memory Designing

简述了CAM存储器(Content Addressable Memory)的主要应用,讨论了采用可编程器件FPGA设计CAM的一般方法和优缺点,针对FPGA设计的CAM不易在线写入的问题,提出了利用FPGA中查找表LUT设计存储单元,实现CAM内容在线可写的新方法。详细论述了基于Xilinx公司最新FPGA设计实现在线可写CAM的技术,通过设计实例验证了方法的实用性,分析了资源消耗和访问速度,表明该方法设计的CAM资源利用率较高、访问速度快、设计方法容易、易于扩展,能够满足内容在线可写的应用要求。

The applications of Content addressable memory （CAM） were introduced. A general method to design CAM with FPGA was discussed. The advantages and disadvantages of FPGA based CAM are discussed as well. A novel method was proposed to design on-line writable CAM with lookup tables of FPGA. The techniques of designing on-line writable CAM with LUTs were discussed in details. A CAM prototype was completed to verify the method. The performances of CAM prototype were analyzed. The simulation results indicated that the resource usage of FPGA was effective and the match sneed of CAM was very fast. So it is suitable for most fast aattern matching applications.