Alarm System Help

Thread Starter

CoolStuffZone

Joined May 14, 2016
1
Need help with the following Homework assignment…

Design a fire alarm system using a 8051 microcontroller. The specs are as follows:

A) If the alarm is detected (one of the switches is activated) it should start flashing 4 LEDS (4 on the right (LEDS 1-4) and 4 on the left (LEDS 5-8), alternating).

B) If the alarm is not detected, the display should show only 2 middle LEDS (LEDS 4 & 5) steadily ON (not flashing) indicating NORMAL operation.

This is the code I’ve come up with so far, but I appear to be stuck. I would appreciate and assistance. Thank you.

Code…

ORG 0H ;Program starting location

MOV A, #0 ;

MOV P2, A ;

MOV A, #OFFH;

MOV P1, A ;

INPUT: MOV A, P1 ;

HERE: JNB A, HERE ;

MOV P2, #1 ;

DELAY:

MOV R3, #15 ;

OUTER:

MOV R2, #240 ;

INNER:

DJNZ R2, INNER ;

DJNZ R3, OUTER ;

RET


SDELAY:

MOV R5, #45 ;put 45 in R5

H3: MOV R4, #242 ;put 242 in R4

H2: MOV R3, #255 ;put 255 in R5

H1: DJNZ R3, H1 ;Decrement R3 keep @ H1 if not zeroed

DJNZ R4, H2 ;Decrement R4 keep @ H2 if not zeroed

DJNZ R5, H3 ;Decrement R5 keep @ H3 if not zeroed

RET ;Return & Go back to line after ACALL



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