back to home page - back to computer structure index - back to 8086 index
8255 IO Controller
General Introduction

Introduction 8255 is an Programmable IO Controller that originally designed to work with 8085/8086/8088 Microprosessors. the Chip simplify the control of multiple IO devices instead of using MUXing technics on the IO mapping IO the 8255 connected with 8086 CPU using Read\Write Logic Pins ( RD_N, WR_N ) and Data BUS it have 3 ports PA, PB and PC, that devided in to 2 groups.	8255 Pins Scematics
Pins Discription ● Data BUS Lane (D 0-7) connected to the Data BUS of 8086 System ● Read\Write Logic Control Pins -       WR_N and RD_N connect to CPU WR_N and RD_N       CS used to disable enable the Controller	High Level Diagram Example of 8255 VHDL Entity (with connect of pins)

Integration with 8086 CPU in a Computer system