Alarm System Help

Discussion in 'Homework Help' started by CoolStuffZone, May 14, 2016.

  1. CoolStuffZone

    Thread Starter New Member

    May 14, 2016
    1
    0
    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



    ;--------------------



    END
     
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