Tutorial Microcontroller 8051

2.3.8. Moving Display

In this lesson, we are going to drive 8 x7 segmen, in this way you can write eight character on multi 7 segmen. We used a multiplexing methode to transfer data for driver transistor consequtively.

Microcontroller Application Seven Segmen
Figure 2.3.5. Driving on Multi 7 Segmen

Step 1st
Build the circuit as shown in figure 2.3.5. As you seen on figure 2.3.5. P2.0 trough P2.7 is connected to driver transistor, and all eight 7 segment is connected to P0.0 trough P0.6 parallelly. Remember, that all we want to do with this lesson is to write ( k-O-n-P-U-t-E-r ) to 1st, 2nd, 3rd, 4th, 5th, 6th, 7th and 8th 7 segmen each sifting the word to the left.

Step 2nd
In this step, you must tipe the assembly program to make your 7 segmen shown some number on 7 segmen, we assume that you have already known the editor, we used MIDE-51 to edit the program. ( Download File asm : exp238.zip ,Download Complete Circuit File : Sevensegmen.PDF )

       org 0h
Begin: mov r1,#150
start1: mov dptr,#word1
        mov r5,#8
        mov r2,#01111111b
again1: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again1
        djnz r1,start1
        mov r1,#150
start2: mov dptr,#word2
        mov r5,#8
        mov r2,#01111111b
again2: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again2
        djnz r1,start2
        mov r1,#150
start3: mov dptr,#word3
        mov r5,#8
        mov r2,#01111111b
again3: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again3
        djnz r1,start3
        mov r1,#150
start4: mov dptr,#word4
        mov r5,#8
        mov r2,#01111111b
again4: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again4
        djnz r1,start4
        mov r1,#150
start5: mov dptr,#word5
        mov r5,#8
        mov r2,#01111111b
again5: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again5
        djnz r1,start5
        mov r1,#150
start6: mov dptr,#word6
        mov r5,#8
        mov r2,#01111111b
again6: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again6
        djnz r1,start6
        mov r1,#150
start7: mov dptr,#word7
        mov r5,#8
        mov r2,#01111111b
again7: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again7
        djnz r1,start7
        mov r1,#150
start8: mov dptr,#word8
        mov r5,#8
        mov r2,#01111111b
again8: clr A
        movc A,@A+dptr
        inc dptr
        mov p2,A
        mov A,r2
        mov p3,A
        rr A
        mov r2,A
        acall delay
        mov p2,#11111111b
        djnz r5,again8
        djnz r1,start8
        ljmp begin
;
delay: mov r3,#10
delay1: mov r4,#10
        djnz r4,$
        djnz r3,delay1
        ret
;
word1: db 10001010b,11000000b,11001000b,10001100b
       db 11000001b,10000111b,10000110b,11001110b
word2: db 11000000b,11001000b,10001100b,11000001b
       db 10000111b,10000110b,11001110b,10001010b
word3: db 11001000b,10001100b,11000001b,10000111b
       db 10000110b,11001110b,10001010b,11000000b
word4: db 10001100b,11000001b,10000111b,10000110b
       db 11001110b,10001010b,11000000b,11001000b
word5: db 11000001b,10000111b,10000110b,11001110b
       db 10001010b,11000000b,11001000b,10001100b
word6: db 10000111b,10000110b,11001110b,10001010b
       db 11000000b,11001000b,10001100b,11000001b
word7: db 10000110b,11001110b,10001010b,11000000b
       db 11001000b,10001100b,11000001b,10000111b
word8: db 11001110b,10001010b,11000000b,11001000b
       db 10001100b,11000001b,10000111b,10000110b
end       
       end

Step 3rd
Safe your assembly program above, and name it with *.asm (for example) Compile the program that you have been save by using MIDE-51, see the software instruction.

Step 4th
Download your hex file ( *.hex ) into the microcontroller by using Microcontroller ATMEL ISP software, see the instruction.After download this hex file you'll see the action of the 7 segmen( of course if your cable connection and your program are corrected ).

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Lesson 1:
T o o l
1.1. Programmer
1.2. Edsim 51
1.3. MIDE-51
1.4. ATMEL ISP

Lesson 2:
Input Output
2.1.LED
2.2.Swicht
2.3.7 Segmen
2.4.LCD Character
2.5.ADC
2.6.DAC
2.7.Motor Stepper
2.8.Keypad

Lesson 3:
Timer Counter
3.1.Basic
3.2.Mode 0
3.3.Mode 1
3.4.Mode 2
3.5.Mode 3

Lesson 4:
Serial Comm.
4.1.Basic
4.2.LED
4.3.Rotate LED
4.2 ADC
4.3.LCD

Lesson 5:
Interuption
5.1.Basic
5.2.Timer
5.2.External