微型机工作时信息输至微机;控制讯号及结果从微机至外部设备,这种信息交换,其方式尽管多种多样,但CPU总是要通过接口电路才能与外设备实现联接。 APPLE-Ⅱ型(又称DJS-033型、或其改进型DW-02又称紫金Ⅱ型)个人微型计算机系统,其主机与用户的控制机或数据采集等外部设备间的接口电路一般不配备,只有若干50线I/O插槽。为了自行配备APPLE-Ⅱ微机的并行接口电路,采用国内易于购得的INTEL系列8255A型可编程并行接口芯片作 Microcomputer information input to the computer work; control signals and results from the microcomputer to external devices, this exchange of information, although a variety of ways, but always through the interface circuit to CPU and external devices to achieve connection. APPLE-Ⅱ type (also known as DJS-033 type, or its improvement DW-02 also known as Zijin Ⅱ type) personal microcomputer system, the host and the user’s control machine or data acquisition and other external devices interface circuit generally not equipped , Only a few 50 line I / O slots. In order to be equipped with their own APPLE-Ⅱ microcomputer parallel interface circuit, using the domestic easy-to-purchase INTEL series 8255A programmable parallel interface chip