Ocean College and School Students Science Projects materials

6 function 8 channel light chaser using 8051.

A 6 function 8 channel light chaser using 8051 is shown here. The hardware and software of this circuit are very simple and the light functions gets repeated one after another  automatically. P1.0 to P1.7  of the microcontroller (AT89S51) are assigned as the output pins. Corresponding LEDs are connected to the output pins through 1K current limiting resistors (R1 to R8). The sequence by which the output pins (P1.0 to P1.7) goes high and low is determined by the program and the LEDs follow this sequence. Circuit diagram of the 6 function chaser using 8051 is shown below.

6 function light chaser using 8051

Program.

START: MOV A,#80H
       MOV R7,#07H
       MOV P1,A
       LCALL DELAY
LABEL1: RR A
        MOV P1,A
        LCALL DELAY
        DJNZ R7,LABEL1
        MOV R7,#07H
LABEL2: RL A
        MOV P1,A
        LCALL DELAY
        DJNZ R7,LABEL2
        MOV P1,#81H
        LCALL DELAY
        MOV P1,#42H
        LCALL DELAY
        MOV P1,#24H
        LCALL DELAY
        MOV P1,#18H
        LCALL DELAY
        MOV P1,#0FFH
        LCALL DELAY
        MOV P1,#00H
        LCALL DELAY
        MOV A,#80H
        MOV P1,A
        LCALL DELAY
        MOV R7,#07H
LABEL3: SETB C
        RRC A
        MOV P1,A
        LCALL DELAY
        DJNZ R7,LABEL3
        MOv P1,#00H
        LCALL DELAY
        MOV A,#0AAH
        MOV P1,A
        LCALL DELAY
        CPL A
        MOV P1,A
        LCALL DELAY
        LJMP START 

DELAY:  MOV R4,#03H
WAIT1: MOV R3,#00H
WAIT2: MOV R2,#00H
WAIT3: DJNZ R2,WAIT3
        DJNZ R3,WAIT2
        DJNZ R4,WAIT1
        RET
        END