用8255实现PC机与智能接口卡间并行通信

Parallel communication between PC and its intelligent interface card using 8255

智能接口卡与其所在主机间实现并行通信的方法有多种,例如可使用锁存器和缓冲器等简单并行接口实现,也可使用双端口存储器、FIFO存储器等方法实现,但这些方法都需考虑隔离问题,硬件电路较复杂。在详细分析8255可编程并行接口芯片工作方式2原理的基础上,以采用8031CPU构成PC机智能接口卡为例,论述了采用两片8255实现PC机与智能接口卡间并行通信的方法,给出了具体接口电路,并详细分析了该接口电路的工作原理及特点。

There are many methods to realize parallel communication between the intelligent interface card and the host computer which the card is inserted it, for example, simple parallel interfaces as flip-latches and buffers are used for this aim, double-port memories and FIFO memories also are used for this, but isolation question should be considered and the hardware electric circuits would be complex ifthese methods be used. Based on detailed analysis for the principle of 8255 programmable parallel interface working mode 2, using an intelligent interface card including a 8031 CPU for PC as an example, a method to realize parallel communication between the PC and the intelligent interface card using two 8255 chips is discussed, a concrete connection electric circuit is illustrated, and its working principle and characteristics are analyzed in detail.