Show a sentence scrolling on array of five 7 segment display.

Project Name: 
Show a sentence scrolling on array of five 7 segment display.

Objective of Project:
Creating a program to show the sentence “750-250=500” scrolling on array of 5 Common Anode 7 segment display.

Circuit Diagram:

List of components:

SL	Name and Description	Quantity
1	MCU 89C2051	1
2	7 segment display ( Common Anode )	5
3	74244 Buffer	1
4	Capacitors 30pf (10 uf 50Volt(1), 100uf 50Volt(1))	2
5	Crystal Q11.059A1	1
6	Voltage regulator 7805	1
7	Bread board	1
8	Connecting wires
9	Battery 9 Volt	1

Printout of Program:

ORG 00H

;; PREP

                MOV DPTR, #CACODE

                MOV R1, #31H                   ; buffer

                MOV R3, #00H                   ; index

                MOV R2, #05H                   ; counter

GETBUFER:

                MOV A, R3

                MOVC A, @A+DPTR

                INC R3

                CJNE A, #'$', OVER

                MOV A, #0FFH                  ; ca code of blank

                MOV R3, #00                      ; index at 00 offset

OVER:

                MOV @R1, A

                INC R1

                DJNZ R2, GETBUFER

AGAIN:

                MOV R2, #05H                   ; counter

                MOV R1, #31H                   ; adjust buffer(30-34h)

                MOV R0, #30H

ADJUST:

                MOV A, @R1

                MOV @R0, A

                INC R0

                INC R1  

                DJNZ R2, ADJUST

                MOV R6, #16                      ; outmost loop

OUTLOOP1:

                MOV R7, #32                      ; outer loop

OUTLOOP2:

                MOV B, #01H                     ; display control code

                MOV R1, #30H                   ; buffer

                MOV R2, #05H                   ; counter

DISP:                                                     ; inner loop

                MOV A, @R1

                MOV P1, A

                MOV P3, B

                LCALL DELY         

                LCALL DELY

                INC R1

                MOV A, B

                RL A

                MOV B, A

                DJNZ R2, DISP

                DJNZ R7, OUTLOOP2

                DJNZ R6, OUTLOOP1

                MOV R1, #35H                   ; append buffer

                MOV A, R3

                MOVC A, @A+DPTR

                CJNE A, #'$', OVER1

                MOV A, #0FFH                  ; ca code of blank

                MOV R3, #0FFh                 ; index at 00 offset

OVER1:

                MOV @R1, A

                INC R3

                SJMP AGAIN

DELY:

                 MOV R5, #0FFh

FIV: DJNZ R5, FIV

                 RET

CACODE:

                 DB 0F8h, 92h, 0C0h, 0BFh, 0A4h, 92h, 0C0h, 0B7h,  92h, 0C0h, 0C0h, '$'

END

Brief Description of Program:

What are the new concepts are given below:-

Value #05h for five display as counter. And then adjust r1 and r2 register. Another section moves

the content of RAM which address is hold by r1 to a. move a value to the content of RAM which

address is hold by r0. Increment r0 and r1. Decrement r2 if not 0 then branches address to ADJUST.

Then set a delay. Move accumulator value to a p1, and move b to p3. We set table value define

byte 0F8h, 92h, 0C0h, 0BFh, 0A4h, 92h, 0C0h, 0B7h,  92h, 0C0h, 0C0h. Each hex code contains a character.

Achievements (Result): 

So, it is showing the sentence “750-250=500” on 5 common anodes 7 segment display at once.