interfacing 7 segment display with 8086 processor

Statement: Program to interface 8086 microprocessor kit with Seven Segment Display and make any digit to Blink

Description:

In this program we interface 8086 microprocessor with Seven Segment Display and diaplay a digit.  To interface with Seven Segment Display,we must be familiar with 8255A PPI, which has three ports which can be used as I/O ports. The ports A, B and C are identified using addresses 19H, 1BH, and 1DH respectively and control register address is 1FH. We use Seven Segment Display structure using the following digit

	Digit	Hexadecimal	Decimal	Binary
8	0 1 2 3 4 5 6 7 8 9	C0 F9 A4 B0 99 92 82 F8 80 90	192 249 164 176 153 146 130 248 128 144	11000000 11111001 10100100 10110000 10011001 10010010 10000010 11111000 10000000 10010000

code: 

Source program:

 MOV AL,10000000B

 OUT PPI_C, AL

STR:   MOV AL, 10011001B

 OUT PPIA,AL

 MOV CX, FFFFH

DEL:    NOP

 NOP

 NOP

 LOOP DEL

 MOV AL, 11111111B

 OUT PPIA, AL

 MOV CX, FFFFH

DEL1:    NOP

 NOP

 NOP

 LOOP DEL1

 JMP  STR

 HLT

Traffic light programming in assembly for 8086

; Traffic ligts test 2 for
; c:\emu8086\devices\Traffic_Lights.exe

; This is just an example of how to set the lights,
; DO NOT RUN AT MAXIMUM SPEED, DO NOT USE REAL CARS.
;)


#start=Traffic_Lights.exe#

name "traffic2"

yellow_and_green equ      0000_0110b
red              equ      0000_0001b
yellow_and_red   equ      0000_0011b
green            equ      0000_0100b

all_red          equ      0010_0100_1001b

start:
nop


; 0,1,2

mov ax, green
out 4, ax

mov ax, yellow_and_green
out 4, ax

mov ax,red
out 4, ax

mov ax, yellow_and_red
out 4, ax


; 3,4,5

mov ax, green << 3
out 4, ax

mov ax, yellow_and_green << 3
out 4, ax

mov ax,red << 3
out 4, ax

mov ax, yellow_and_red << 3
out 4, ax



; 6,7,8

mov ax, green << 6
out 4, ax

mov ax, yellow_and_green << 6
out 4, ax

mov ax,red << 6
out 4, ax

mov ax, yellow_and_red << 6
out 4, ax



; 9,A,B

mov ax, green << 9
out 4, ax

mov ax, yellow_and_green << 9
out 4, ax

mov ax,red << 9
out 4, ax

mov ax, yellow_and_red << 9
out 4, ax


; all

mov ax, all_red
out 4, ax

mov ax, all_red << 1  ; all yellow
out 4, ax

mov ax, all_red << 2  ; all green :)
out 4, ax


jmp start