Down Counter with Seven Segment Display using 8051

By:Hammad, Abdul Samad, Muhammad Raza, Abdul Rauf, Sajjad Buledi.

Introduction

Down counter with seven segment display using 8051 ic. This counter counts down from '9-0' when we press the button.

Working

This is a circuit of simple down counter with seven segment display using 8051 micro controller IC. The main principle of this circuit is to decrements the values on seven segment display by pressing the button. When button is pressed value on the display is decremented by one value.The value on the display can be decremented from '9-0'. Down counter is used for counting number of objects passed through a point.It is used to count number of persons exiting a room.

Source Code

ORG 00H SW1 EQU P1.0 LOOP1: JNB SW1,Y2 SJMP LOOP1 Y2:MOV P2,#01101111B ACALL DELAY V2:JNB SW1,Y3 SJMP V2 Y3:MOV P2,#01111111B ACALL DELAY V3:JNB SW1,Y4 SJMP V3 Y4:MOV P2,#00000111B ACALL DELAY V4:JNB SW1,Y5 SJMP V4 Y5:MOV P2,#01111101B ACALL DELAY V5:JNB SW1,Y6 SJMP V5 Y6:MOV P2,#01101101B ACALL DELAY V6:JNB SW1,Y7 SJMP V6 Y7:MOV P2,#01100110B ACALL DELAY V7:JNB SW1,Y8 SJMP V7 Y8:MOV P2,#01001111B ACALL DELAY V8:JNB SW1,Y9 SJMP V8 Y9:MOV P2,#01011011B ACALL DELAY V9:JNB SW1,Y10 SJMP V9 Y10:MOV P2,#00000110B ACALL DELAY V11:JNB SW1,Y12 SJMP V11 Y12:MOV P2,#00111111B ACALL DELAY delay: mov r1, #10 loop41:mov r2, #200 loop31:mov r3, #250 loop21:djnz r3, loop21 djnz r2, loop31 djnz r1, loop41 ret END

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