This document describes a number guessing game that uses an 8085 microprocessor and 8255 I/O interface chip. The game allows a player to think of a number between 0 and 99, then scan a table to determine which DIP switches to flip on an 8-way switch in order to display the chosen number on 7-segment displays. The 8255 chip interfaces between the 8085 and the switches and displays, reading the switch input and controlling the display output.

1. NUMBER GUESSING GAME
A 8085 PROJECT

2. THE GAME
•A very simple game. In this game the player thinks
of any number between 0 to 99.
•Then he scans the eight groups of numbers given in
the eight boxes in the table.
•Each group corresponds to a specific switch
(indicated on the top of each group) on an 8-way DIP
switch.
•After having scanned all the eight boxes and
switching on the relevant DIP switches, the number
thought of by the person is displayed on the 7-
segment displays.
•All this is done by I/O interfacing of 8255 with 8085.
The input given by the switches and the output
displayed on 7-segment displays.

3. THE TABLE

4. THE EXPLANATION
•Suppose you want to display 47. For this, 4 is to
be displayed in tens position and 7 in units
position. In order to generate 4 (binary 100) on the
display 1, switch S2 is to be turned on.
•To display 7 (binary 111) on the display 2,
switches S6, S7, and S8 are to be turned on.
•Thus to generate 47, switches S2, S6, S7, and S8
are to be turned on. The number 47 is placed in
groups 6, 7, 8, and 2.
•So when you spot 47 in these groups, switch on
the same combination of
switches.

5. CIRCUIT DIAGRAM