Aim:
To display 8086 number in
a four seven segment Common Anode LED display.
Hardware and Software Required:
8086 kit, LED Display Unit
Hardware Description:
Seven segment displays
are important display units in Electronics and widely used to display
numbers from 0 to 9. It can also display some character alphabets like
A,B,C,H,F,E etc
There
are two types of 7 segment displays: Common Anode and Common Cathode:
Common
Anode: In this all the Negative
terminals (cathode) of all the 8 LEDs are connected together (see diagram
below), named as COM. And all the positive terminals are left alone.
Common
Cathode: In this all the positive terminals
(Anodes) of all the 8 LEDs are connected together, named as COM. And all the
negative thermals are left alone.
A table has been given
below for all the numbers while using Common Anode 7 segment.
|
Digit to Display
|
h g f e d c b a
|
Hex code
|
|
0
|
11000000
|
C0
|
|
1
|
11111001
|
F9
|
|
2
|
10100100
|
A4
|
|
3
|
10110000
|
B0
|
|
4
|
10011001
|
99
|
|
5
|
10010010
|
92
|
|
6
|
10000010
|
82
|
|
7
|
11111000
|
F8
|
|
8
|
10000000
|
80
|
|
9
|
10010000
|
90
|
Code:
OUTPUT 2500AD
ORG 2000H
MOV DX,FFE6H ;Configure
all 8255 ports
MOV AL,80H ;as
output.
OUT DX,AL
LOOP4: MOV SI,2100H ;Initialise pointer
LOOP3: MOV CH,04H ;4 charecters/group
LOOP2: MOV BL,08H ;8 segments/charecter
MOV AL,[SI] ;get the
display code
INC SI ;Increment
pointer
LOOP1: ROL
AL,1 ;get 1 data bit
MOV
DX,FFE2H
OUT
DX,AL ;o/p bit to portb
MOV
AH,AL
MOV
AL,01H ;o/p clock to
MOV
DX,FFE4H ;shift register
OUT
DX,AL
DEC
AL
OUT
DX,AL
MOV
AL,AH
DEC
BL ;all bits over?
JNZ
LOOP1 ;no,continue
DEC
CH ;all charecters over?
JNZ
LOOP2 ;no,continue
CALL DELAY
;all
groups over?
;JNZ LOOP3 ;no,continue
JMP
SHORT LOOP4
DELAY: MOV CX,0FFFFH
XX: DEC CX
JNZ
XX
RET
;Display code table
ORG
2100H
STRING: DB 080H,0C0H,080H,080H
END
