一种构建双端口共享存储器的方法

基于双CPU共享RAM技术，从经济实用的角度出发，提出了一种利用单端口存储器构建双端口共享存储器的方法。根据62256单端口存储器的工作原理和结构设计特点，利用单向缓冲器芯片74ALS244对存储器的地址总线、控制总线进行扩展，利用双向缓冲器芯片74ALS245对存储器的数据总线进行扩展，存储器的地址线、数据线和控制线分别由单路变为双路，再通过选通信号实现对各路总线的读写控制。经扩展的单端口存储器可实现双端口存储器的全部功能，具有成本低、容量大、性能稳定的优点，可广泛应用于硬件设计。

A Method of Constructing Dual-port Shared Memory

Based on the technology of dual-CPU sharing RAM, and from the perspective of economy and practical application, a design method is proposed utilizing a single-port memory to construct a dual-port shared memory in this paper. According to the operation principle and the structure characteristics of the single-port memory 62256, the address bus, the control bus and the data bus are extended using the unidirectional buffer chip 74ALS244 and the bidirectional buffer chip 74ALS245, respectively. The address bus, data bus and control bus are changed into double channel from single channel. After that, the reading and writing con- trol of the buses are achieved through strobe signals. All functions of the dual-port shared memory are obtained using extended single-port memory. Having advantages of low cost, large capacity and stable performance, this technology can be widely used in hardware design.