8086 programs

Following is the Assembly language program for a real time clock

Code:

LCALL 061D

AGAIN MOV DPTR, #2845

REPEAT DEC82 ; Decrement DPL

MOVX A,@DPTR

MOV R3,A

MOV R5,#02

LCALL 059E

MOV A,20

LCALL 2006

MOVA,82

CJNE A,#42; REPEAT (ED)

MOVA,#OD ; OD = ASCII FOR ENTER

LCALL 2006

LJMP; AGAIN ( 6003 )

To change the RTC

2844-hrs

2843-minutes

2842-seconds

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Labels: 8086, Assembly Language, c program, real time clock

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Program to interface DAC using 8255 and generate square waveform

Program to interface DAC using 8255 and generate square waveform

The following is the assembly language using DAC to interface with 8255 and

generate a square wave on CRO. Here in the code, we use two delay elements

one for the rising part of the wave and the other delay element to reach zero i.e

decrement. Certain value chosen is delayed or sustained for a time period to

form the square wave. The two loops used in the program are iterated to repeat

cycles of a square wave.

Code:

MOV DX,8807 : DX is loaded with control word register address of 8255

MOV AL,80

OUT DX,AL : Contents of AL are transferred to portA of 8255

MOV DX,8801 : DX is loaded with Port A address of 8255

Begin MOV AL,00

OUT DX,AL ; Contents of AL are transferred to portA of 8255

MOV CX,00FF

Delay1 Loop Delay1

MOV AL,FF

http://1.bp.blogspot.com/_cdJYq16p3_g/SP3qzao8kGI/AAAAAAAAANo/DlPPqVG6Nd4/s1600-h/SquareWave.jpg

OUT DX,AL : Contents of AL are transferred to portA of 8255

MOV CX,00FF : CX is loaded with 00FFH

Delay2 Loop Delay2 : Repeat until CX=0

JMP Begin ; Repeat the same

The expected square wave can be observed as in the figure shown. Thus we

programed in assembly language to interface DAC using 8255 to generate a

square waveform.

Related links

Ebooks for micro processors and micro controllers

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Labels: 8086, 8255, Assembly Language, generate square waveform, square

wave


Assembly language program to find square root of 8-bit number

Following is the assembly language program to find square root of 8-bit number.

In this program we initially load the index registers with specified values. We

load the value of the number into SI Register. Then using a few logical steps as

mentioned in the code i.e JMP insctructions we find the square root of a 8-bit

number.

Code:

MOV SI,2000

MOV DI,4000

MOV CX,0001

MOV BX,0000

MOV AL,[SI] ; Load AL with the value given as at SI

UP SUB AL,CL

JL down ; jump to down label

INC BL

ADD CL,02 ; add 2 to contents of CL register

JMP UP ; jump to up label

DOWN MOV[DI],BL

INT A5

Thus by implementing the above code we can find the square root of 8-bit

number

Related posts

square root of hexa decimal number

Ebooks

You might be also interested in:

:: Find Square Root of a hexadecimal number in assembly language

:: common intreview questions on 8086

:: Assembly Language Source Codes

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Labels: 8086, Assembly Language, square root

O C T 1 5 , 2 0 0 8

Program to interface stepper motor with 8086 and rotate with anti clock wise direction in full stepping

The following program is to interface stepper motor with 8086 and rotate with

anti clock wise direction in full stepping. The purpose of this is to observe and

control the stepping action of the motor using assembly language code. The

code is also practically illustrated with two live demonstrations on how speed of

the motor varies if one of the instruction codes is changed to a new value.

Code:

MOV DX,8807 : Load DX with control word register address of 8255

MOV AL,80 : load control word 80 into AL

OUT DX,AL: Contents of AL are loaded into control word register of 8255

MOV DX,8801: Load PortA address of 8255 into DX

MOV AL,33: Load value 33 into AL

Again OUT DX,AL: Contents of AL are loaded into control word register of 8255

MOV CX,0100: set counter to delay

Loop Again

ROL AL,1 : Rotate left by 1

JMP Again : Unconditional jump to label again

Following is the practical illsutration of the output for the above given code.

The instruction MOV CX,0100 can be changed to a new value in order to vary

the speed.

So, for instance lets say MOV CX,7000. Following is the video demonstration of

how the speed varies if the value is changed in the above instruction


Thus by changing the instruction the speed of the stepper motor can be varied

according with interfacing it to an 8086 microprocessor for full stepping

Related posts:

Interfacing a stepper motor with an AVR Microprocessor

Interfacing a stepper motor with pic micro controller

Interfacing a stepper motor to 8086 using 8255

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S E P 2 8 , 2 0 0 8


program to find factorial of given numbers

following is the assembly language program to find factorial of given numbers

MOV SI , 2000

MOV DI,2002

MOV CX,[SI]

MOV AX,CX ; Move contents of CX to contents of AX register

DEC CX ; Decrement CX

UP: MUL CX

DEC CX ; Decrement CX

JNZ; UP ; Jump if not zero

MOV [DI], AX ; Load the values of AX into location given by DI

INT A5; Halt the program


:: Troubleshooting a simple 8086 microprocessor based microcomputer

:: centigrade (celsius) to fahrenheit calculation for 8086 Assembly Language

:: Data transfer instructions of 8086 microprocessor

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Program to find arithmetic mean of n numbers

Program to find arithmetic mean of n numbers

CLC ; clear carry flag

MOV SI , 2000

MOV DI, 2050

MOV CX, 0000 ; Load CX register with the value given by 0000

MOV AX,0000

MOV CL,[SI]

MOV DL,CL

A1: INC SI ; Increment SI contents

ADD AL,[SI] ; ADD AL with the value given by that at SI and store in AL

LOOP AI ( 1011) ; Repeat until CX=0

DIV BL; Divide AX With the value given by BL

MOV [DI],AX ; Load the value in AX into as location at DI

INT A5 ; HALT

Thus with the above code the arithmetic mean of n numbers can found

accordingly.

sample input:

0000:2000 array size

0000:20001 array elements

from 2001 location

Output

0000:2050 Result


::Interfacing pic microcontroller with LCD

:: Serial Port interfacing with atmega

:: TCP/IP on PIC 18 series

0 comments

assembly language program to reverse a given string

Following is the assembly language program to reverse a given string.

MOV AX @ DATA ; AX IS INITIALIZED WITH DATA

MOV DS AX ; AX IS MOVED INTO DS

MOV CX 0005H ; CX IS INITIALIZED TO 5

LEA SI A1 ; SI IS HAVING LEAD E.A OF A1

LEA DI A2; DI IS HAVING LEAD E.A OF A2

ADD SI 0004

AGAIN: MOV AL[SI]

MOV [DI]AL ; AL IS MOVED INTO DI

DEC SI

INC DI

LOOP AGAIN

INT 3 ; INTERRUPT

END

Using the above code if an Input for instance ' ad-cole': 0006 is given then the

output will be shown as

DS: 0011: 16

10A0: 0010 : 65, 64 , 63 , 62 , 61 05 e d c b a





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S E P 2 3 , 2 0 0 8



stack program for push and pop

following is the assembly language program for push and pop operations in a

stack.

code segment

main:

mov sp,1000h initialize SP to point to stack

mov ax,1234h

mov bx,5678h

mov cx,9abcdh

push ax

push cx

pop ax

pop ax

pop bx

pop cx

mov bx,0200h

mov w[bxx],1234h; address 0200 holds 1234

push [0200h]

push[bx]

mov bx,0210h

pop [bx]

pop[0212h]

imp main ; demo again

code ends

This program establishes the stack at 0100h and puts some random numbers in

registers AX , BX , CX. AX is pushed on the stack that stores it at SS:OFFFh(MSB)

and SS:0FFEh{LSB}. BX and CX are stored in similar manner with the attendant

decrement of SP bt 2 for each push. The contents of the stack are then popped

from the stack, in reverse order.

8086 program to find GCD of two 2 numbers

Euclid (a Greek mathematicians and philosopher of about 300 BC) describes this

algorithm in Propositions 1 and 2 of Book 7 of The Elements, although it was

probably known to the Babylonian and Egyptian mathematicians of 3000-4000

BC also.

If we try it with an two numbers, the final non-zero remainder is the greatest

number that is an exact divisor of both our original numbers (the greatest

common divisor)

Here is the program

mov ax,4000h

mov ds,ax

mov si,0000h

mov al,num1 ;num1 is first no.

mov cl,num2 ;num2 is second no.

mov ah,00h

cmp al,cl

ja next

xchg al,cl

next: mov bl,cl

div cl

cmp ah,00h

je down

mov al,cl

mov cl,ah

mov ah,00h

jmp next

down mov result,bl ;result is the mem.loc.

;where gcd is to be stored

hlt


:: options available for int 21h instruction

:: Answers of Microprocessor(8085) & Electronics FAQ

:: The 8085 Microprocessor Architecture Microprocessors & Interfacing

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Labels: 8086, Assembly Language, Program

J U L 6 , 2 0 0 8


decimal addition program for 8086

This program will add two decimal numbers

LXI H,2200H

MOV A,M

INX H

ADD M

DAA

STA 2300H

HLT

DAA will convert HEX to valid BCD number

now the program can be easily understood


:: 8051 or PIC microcontroller which is better

:: Effective addresses

:: Floating Point Initializations

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Data transfer instructions of 8086 microprocessor

General purpose byte or word transfer instructions

MOV

copy byte or word from specified source to specified destination

PUSH

copy specified word to top of stack.

POP

copy word form top of stack to specified location

PUSHA

copy all registers to stack

POPA

copy words from stack to all registers.

XCHG

Exchange bytes or exchange words

XLAT

translate a byte in AL using a table in memory.

These are I/O port transfer instructions

IN

copy a byte or word from specific port to accumulator

OUT

copy a byte or word from accumulator to specific port

Special address transfer Instructions

LEA

load effective address of operand into specified register

LDS

load DS register and other specified register from memory

LES

load ES register and other specified register from memory

Flag transfer instructions

LAHF

load AH with the low byte of flag register

SAHF

store AH register to low byte of flag register

PUSHF

copy flag register to top of stack

POPF

copy word to top of stack to flag register


:: Assembly Language Programs to compute an expression

:: Interfacing Analog-to-Digital converter to 8086 using 8255

:: Interfacing Digital-To-Analog converter to 8086 using 8255

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M A R 2 9 , 2 0 0 8


centigrade (celsius) to fahrenheit calculation for 8086 Assembly Language

; this program prints out the result in binary code.

; to see result in hexadecimal or decimal form click vars.

name "celsi"

org 100h

jmp start

tc db 10 ; t celsius.

tf db 0 ; t fahrenheit.

result1 db ? ; result in fahrenheit.

result2 db ? ; result in celsius.

start:

; convert celsius to fahrenheit according

; to this formula: f = c * 9 / 5 + 32

mov cl, tc

mov al, 9

imul cl

mov cl, 5

idiv cl

add al, 32

mov result1, al

mov bl, result1

call print ; print bl

; convert fahrenheit to celsius according

; to this formula: c = (f - 32) * 5 / 9

mov cl, tf

sub cl, 32

mov al, 5

imul cl

mov cl, 9

idiv cl

mov result2, al

mov bl, result2

call print ; print bl

; wait for any key press...

mov ah, 0

int 16h

ret ; return to the operating system.

; procedure prints the binary value of bl

print proc near

pusha

; print result in binary:

mov cx, 8

p1: mov ah, 2 ; print function.

mov dl, '0'

test bl, 10000000b ; test first bit.

jz zero

mov dl, '1'

zero: int 21h

shl bl, 1

loop p1

; print binary suffix:

mov dl, 'b'

int 21h

; print carrige return and new line:

mov dl, 0Dh

int 21h

mov dl, 0Ah

int 21h

popa

ret ; return to the main program.

print endp

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Labels: 8086, Assembly Language, celsius, centigrade, fahrenheit, temperature

M A R 2 6 , 2 0 0 8


Troubleshooting a simple 8086 microprocessor based microcomputer

This post will teach you how to troubleshoot a simple microcomputer system

such as an SDK-86 board

Identify the Symptoms

make the list of symptoms that you find.they to find wether the proble is with

the system or the it is with how the person is use the machine.

Make a careful visual and tactile inspection

check for the components that have been extensively hot.

check to see that all ic are firmly seated in there sockets and that IC's have no

bent pins.

check for broken wires and loose connections or a thin film of dust etc.

ome meter check to verify your suspicions.

Check the power supply

determine the power supply voltages for the manual and check the supply

voltages directly on the appropriate pins of some IC's to make sure the voltage

is actually getting there.

Do a signal Rool Call

make a quick check of some key signals around the CPU of the microprocessor.

if the problem is a bad IC this can help point you towards the one that is bad.

check if clock signals is present with the oscilloscope.

check if CPU is putting out control signals such as RD WR and ALE.

check the bus line to see if there is any activity on the buses. if there is no

activity on these buses then the common problem is that the CPU is stuck on

hold wait halt or reset condition or by afilure od some TTL devices.

perform check on the RAM and ROM and port decoders.

Systematically substitute socketed IC's

the easiest case of substitution is that where you have two identical

microprocessor one that works and one that doesn't and the IC's of both units

are in the sockets for this case you can use the working system to test the IC's

from the non working system.

Troubleshoot soldered in IC's

Equipment for troubleshooting Microcomputers

Logical Analyzers

a logical analyzer is very powerfully troubleshooting tool but to use it effectively

you need some detailed knowledge ans d program listing for the system that

you are trying to troubleshoot.

for detailed steps for the trouble shooting you can refer the book microprocessor

and interfacing by DOUGLAS V HALL . This post is based on that the steps given

in that book


:: Assembly Language Programs to compute an expression

:: Interfacing Analog-to-Digital converter to 8086 using 8255

:: Interfacing Digital-To-Analog converter to 8086 using 8255

1 comments

Labels: 8086, Troubleshooting

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free and open source 8086 Microprocessor Emulator

i8086emu

this is a free and open source Intel 8086 based microprocessor cross-platform

emulator. It has support for dynamically loadable device plugins and some

peripherals like a PIT, PIC, 8-segment-displays, buttons and leds. i8086emu

comes with an ncurses and an GTK-2 gui

here is the screen short of the emulator this can work major operating systems

likeAll 32-bit MS Windows (95/98/NT/2000/XP), All POSIX (Linux/BSD/UNIX-like

OSes) Linux this software is downloaded more than 4500 time from

sourceforge.net

dowload it here download microprocessor emulator

http://i8086emu.sourceforge.net/images/gtkgui.jpg





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Labels: 8086, emulator, microprocessor, software

M A R 8 , 2 0 0 8


Program to display ASCII characters on the display unit

this is the program to display ascii characters on the screen it is written in

assembly language and can work of 8086 microprocessors

.model small

.stack

.data

.code

; program starting

main proc

mov dl, 00h

lop: mov ah, 02h

int

21h

inc dl

jnz lop

mov ax,4c00h

int 21h

main endp

end main

; end of the program


:: Interfacing Stepper Motor to 8086 using 8255

:: MASM 611 SOFTWARE

:: bit reversal and sorting programs

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Labels: 8086, Assembly Language, microprocessor, Program

M A R 2 , 2 0 0 8


why there are two ground pins in 8086

here are the different answers

first one :

1 for analog n other for digital ground as i ve heard..the diff b/w analog n digital

ground is digital ground doesnt have transient currents sumthin like that i heard

dont knw in detail..

second one :

several pins of 8086 are multiplexed (means they have different functions in

different situations). the functions of those pins are controlled by these ground

pins. the two functions of processor is grouped in two groups namely 'min mode

operation' and 'max mode operation'.

third one :

there are two pins to support max mode and min mode.....one of the mode is

multiprocessor mode i.e. in ithis mode u can connect two or more

multiprocessors to work in cooperation. if both pin r grounded it means single

procesor mode..

last one :

consider a circuit where ur 8086 has to be activated only when certain condition

is met. say the output of a logic circuit is low. the output pin of this device is

connected to the gnd pin of 8086. when ever the out put pin is low there is a

voltage diff between vcc and gnd pins of 8086 and 8086 is activated. so the

logic device output pin acts a current sink. the sinking capacities of normal ttl

devices are far less compared to the current sourced by a 8086 up. hence 2 gnd

pins to split current from 8086 and ensure the current at gnd pin of 8086 does

not exceed the sinking capacities of the peripherals.


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Labels: 8086, ground pin

F E B 2 7 , 2 0 0 8

Assembly Language Source Codes

Here is the list of programs in assembly language with complete source code is

provided

Assembler Source Code for emu8086 microprocessor emulator and

compatible assemblers (16 bit) simply copy these codes and past them on

your editor

http://www.emu8086.com/dr/asm2html/assembler_source_code/

it contains list of programs like

Input 8 bit binary number and print out its decimal equivalent.

This is a very basic example of a tiny OS. Your own Operating System that

runs from floppy drive - easy!

This example shows how to add huge unpacked BCD numbers

Calculate the sum of elements in V1 array, store result in V2.

How CMP instruction sets the flags.

See how to operate with Octal, Binary and Decimal values.

Learn how to set and get file attributes, in other words how to make file

Read Only or Hidden.

This is an example of AAS instruction, it is used to subtract huge BCD

numbers.

This sample gets two numbers from the user, calculates the sum of these

numbers, and prints it out.

This sample shows how to use CMPSW instruction to compare strings.

Make your own interrupts - Custom_Interrupt.asm

Encryption in Assembly Language

This sample gets the number from the user, and calculates factorial for it.

Supported input from 0 to 8 inclusive!

Call a procedure from another segment or interrupt.

This program calculates linear equation: ax + b = 0 The result is printed

with floating point.

This example prints out The easiest and the fastest way to print "Hello

World!" using DOS INT 21h (still works under Windows XP in Dos prompt).

This example converts 2 digit Hex value into numeric value and decimal

string representation (so that it can be easily printed if required).

Keyboard example - keybrd.asm

A very handy code that can be assembled into a very tiny utility to make

floppy boot records and tiny operating systems.

This sample shows the use of input and output string functions of

emu8086.inc

This sample shows how to use SCASW instruction to find a WORD (2

bytes).


:: Temperature Control system using 8086

:: Traffic light control system using 8086

:: Assembly Language Program to serve NMI

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Assembly Language Program to be executed when NMI is generated

Assembly Language Program to be executed when NMI is generated

AIM:To write Assembly Language Program to be executed when NMI is

generated

APPARATUS:-

Microprocessor trainer kit & power supply.

NON MASKABLE INTERRUPT (NMI)

NMI is an edge triggered input pin which causes Type-2 interrupt. The NMI is not

mask able internally by software. A transition from low to high initiates the

interrupt response at the end of the current instruction. This input is internally

synchronized.

When an external device interrupts the CPU at the interrupt pin NMI and the CPU

is executing an instruction of a program. The CPU first completes the execution

of current instruction. The IP is then incremented by one to point next

instruction. The CPU then acknowledges the requesting device on its INTA pin

immediately for NMI. After an interrupt is acknowledged, the CPU computes the

vector address from the type of the interrupt that may be passed to interrupt

structure of the CPU internally or externally (for NMI vector address is 00008 H).

The contents of PSW, CS & IP are next pushed on stack. The contents of IP & CS

now points to the address of the next instruction in main program from which

the execution is to be continued after executing the ISR. The control is then

transferred to Interrupt Service Routine for serving the interrupting device. The

new address is found out from the interrupt vector table (for NMI [00009:00008]

= ISR IP & [0000B:0000A] = ISR CS. The execution of ISR starts. At the end of

ISR the last instruction should be IRET. When CPU executes IRET instruction the

IP, CS & PSW is popped back from the stack and the execution continued from

address received by IP & CS.

WRITE THIS PROGRAM AT 0000:4000 H MEMORY LOCATION AND

EXECUTE IT

0000:4000 MOV AX,0FFFFH

0000:4003 MOV BX,0FFFFH

0000:4006 ADD AX,BX

0000:4008 HLT

0000:4009

WRITE THIS PROGRAM AT 0000:4100 H MEMORY LOCATION AND

EXECUTE IT

0000:4100 MOV AX,0000H

0000:4103 MOV DS,AX

0000:4105 MOV AL,00H

0000:4107 MOV [0008],AL

0000:410A MOV AL,40H

0000:410C MOV [0009],AL

0000:410F MOV AL,00H

0000:4111 MOV [000A],AL

0000:4114 MOV AL,00H

0000:4116 MOV [000B],AL

0000:4119 HLT

0000:411A

NOW PRESS NMI BUTTON ON 8086 MICROPROCESSOR KIT






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Labels: 8086, 8255, Experiment, microprocessor, NMI, Program

F E B 9 , 2 0 0 8


Traffic light control system using 8086

AIM:-

To develop Traffic light Control system using 8086

APPARATUS:-

Microprocessor trainer kit, Traffic light controller kit, power supply, data cable

etc

THEORY:-

Traffic light controller interface module is designed to simulate the function of

four way traffic light controller. Combinations of red, amber and green LED’s are

provided to indicate Halt, Wait and Go signals for vehicles. Combination of red

and green LED’s are provided for pedestrian crossing. 36 LED’s are arranged in

the form of an intersection. A typical junction is represented on the PCB with

comprehensive legend printing.

At the left corner of each road, a group of five LED’s (red, amber and 3 green)

are arranged in the form of a T-section to control the traffic of that road. Each

road is named North (N), South(S), East (E) and West (W). LED’s L1, L10, L19 &

L28 (Red) are for the stop signal for the vehicles on the road N, S, W, & E

respectively. L2, L11, L20 & L29 (Amber) indicates wait state for vehicles on the

road N, S, W, & E respectively. L3, L4 & L5 (Green) are for left, strait and right

turn for the vehicles on road S. similarly L12-L13-L14, L23-L22-L21 & L32-L31-

L30 simulates same function for the roads E, N, W respectively. A total of 16

LED’s (2 Red & 2 Green at each road) are provided for pedestrian crossing. L7-

L9.L16-L18, L25-L27 & L34-L36 (Green) when on allows pedestrians to cross and

L6-L8, L15-L17, L24-L26 & L33-L35 (Red) when on alarms the pedestrians to

wait.

To minimize the hardware pedestrian’s indicator LED’s (both red and green are

connected to same port lines (PC4 to PC7) with red inverted. Red LED’s L10 &

L28 are connected to port lines PC2 & PC3 while L1 & L19 are connected to lines

PC0 & PC1 after inversion. All other LED’s (amber and green) are connected to

port A & B.

WORKING:-

8255 is interfaced with 8086 in I/O mapped I/O and all ports are output ports.

The basic operation of the interface is explained with the help of the enclosed

program. The enclosed program assumes no entry of vehicles from North to

West, from road East to South. At the beginning of the program all red LED’s are

switch ON, and all other LED‘s are switched OFF. Amber LED is switched ON

before switching over to proceed state from Halt state.

The sequence of traffic followed in the program is given below.

a) From road north to East

From road east to north

From road south to west

From road west to south

From road west to north

b) From road north to East

From road south to west

From road south to north

From road south to east

c) From road north to south

From road south to north

Pedestrian crossing at roads west & east

d) From road east to west

From road west to east

Pedestrian crossing at roads north & south

ASSEMBLY LANGUAGE PROGRAMS:-

MODEL SMALL

.STACK 100

http://bp2.blogger.com/_cdJYq16p3_g/R63iAFAD3oI/AAAAAAAAADA/Kmkoy8hOvok/s1600-h/table.PNG

.DATA

CWR EQU 0FFC6 H

PORTA EQU 0FFC0 H

PORTB EQU 0FFC2 H

PORTC EQU 0FFC4 H

.CODE

START:

MOV AX,@DATA

MOV DS,AX

MOV AL,80H

MOV DX,CWR

OUT DX,AL

MOV AL,F3H

MOV DX,PORTC

OUT DX,AL

MOV AL,FFH

MOV DX,PORTA

OUT DX,AL

MOV AL,FFH

MOV DX,PORTB

OUT DX,AL

MOV CL,03H

CALL DELAY

TOP:

MOV AL,EEH

MOV DX,PORTA

OUT DX,AL

MOV AL,EEH

MOV DX,PORTB

OUT DX,AL

MOV CL,02H

CALL DELAY

MOV AL,FCH

MOV DX,PORTC

OUT DX,AL

MOV AL,7DH

MOV DX,PORTA

OUT DX,AL

MOV AL,57H

MOV DX,PORTB

OUT DX,AL

MOV CL,15H

CALL DELAY

MOV AL,E7H

MOV DX,PORTB

OUT DX,AL

MOV AL,FDH

MOV DX,PORTA

OUT DX,AL

MOV AL,EDH

MOV DX,PORTA

OUT DX,AL

MOV CL,02H

CALL DELAY

MOV AL,F7H

MOV DX,PORTB

OUT DX,AL

MOV AL,F0H

MOV DX,PORTC

OUT DX,AL

MOV AL,F1H

MOV DX,PORTA

OUT DX,AL

MOV CL,15H

CALL DELAY

MOV AL,FBH

MOV DX,PORTA

OUT DX,AL

MOV AL,FBH

MOV DX,PORTB

OUT DX,AL

MOV AL,50H

MOV DX,PORTC

OUT DX,AL

MOV CL,15H

CALL DELAY

MOV AL,FEH

MOV DX,PORTA

OUT DX,AL

MOV AL,FEH

MOV DX,PORTB

OUT DX,AL

MOV CL,03H

CALL DELAY

MOV AL,FFH

MOV DX,PORTA

OUT DX,AL

MOV AL,AFH

MOV DX,PORTC

OUT DX,AL

MOV AL,EEH

MOV DX,PORTA

OUT DX,AL

MOV AL,EEH

MOV DX,PORTB

OUT DX,AL

MOV CL,02H

CALL DELAY

MOV AL,BFH

MOV DX,PORTA

OUT DX,AL

MOV AL,BFH

MOV DX,PORTB

OUT DX,AL

MOV CL,15H

CALL DELAY

JMP TOP

DELAY:

MOV BX,10H

D1:

MOV CX,0FFFFH

D2:

LOOP D2

DEC BX

JNZ D1

INT 03H

END START

PROCEDURE:-

1. Connect power supply 5V & GND to both microprocessor trainer kit & Traffic

light controller interfacing kit.

2. Connect data bus between microprocessor trainer kit & Traffic light

controller interfacing kit.

3. Enter the program to control Traffic light.

4. Execute the program by typing GO E000:0B80 ENTER.

5. Observe the LED’s on traffic light controller PCB.






10 comments

Labels: 8086, Experiment, microprocessor, Program, Traffic light control system

J A N 2 8 , 2 0 0 8

Temperature Control system using 8086

AIM:-

To develop Temperature Control system using 8086

APPARATUS:-

Microprocessor trainer kit, Temperature controller kit, power supply, data cable etc

THEORY:-

Temperature control system involved interfacing successive approximation ADC and typical

method of measuring and controlling the temperature using microprocessor. ADC is among the

most widely used devices for data acquisition. A digital computer uses binary values, but in

physical world everything is analog, temperature, pressure, humidity, and velocity are few

examples of physical quantities that we seal with every day.

Temperature measurement is of great importance in industry as most of the processes are

temperature dependent. A number of devices and schemes have been used over the years, for the

measurement of temperature. Typical sensors include devices like thermocouples, thermostats,

RTD’s and semiconductor sensor.

This system uses semiconductor sensor AD590 to monitor the temperature of water bath. The

AD590 is basically a PTAT (proportional to absolute temperature) current regulator. It generates

a current O/P of 1µA/K above absolute zero temperature that is -2730C. Thus at 00C the current

O/P will be 273µA and 250 if will be 298µA and 373mV at 1000. This O/p is buffered through an

OPAMP having a gain of 10. To enable easy equivalence between the transducers O/P in volts

and the measured temperature a calibration procedure needs to be done.

WORKING:-


8255 is interfaced with 8086 in I/O mapped I/O. port A (PA0-PA7) as input port is connect to

data lines of ADC, PB0, PB1, PB2 lines of port B for channel selection, PC2 connected to Start

of conversion (SOC) and PC3 to O/P enable. Channel 1 of ADC is used to input analog signal,

Channel 0 of ADC for temperature controller.

ADC will give binary equivalent of the I/P voltage. Input will vary from 0 to 5V (0 to 100 degree

C) and the ADC O/P varies from 00-FFH. So 5V/100 i.e. 5000mvs/100 gives 50mvs/ 0C. And the

counts for indication of temperature are taken as 2.5 (256/100) per degree C.

AC supply to the external heating element is controlled through the onboard Relay, based on the

set value. When the temperature of the heating element (which is sensed by AD590, AD590

output is analog which is converted to digital by ADC) is less than the set value (reference value)

heating element will be switched ON and when temperature crosses the set temperature AC

supply is turned OFF.

MODEL SMALL

.STACK 100

.DATA

START:

PORTA EQU FFC0H ; PORTA address

PORTB EQU FFC2H ; PORTB address

PORTC EQU FFC4H ; PORTC address

CTL EQU FFC6H ; Control port address

CTL_BYTE EQU 98H ; 8255 control reg.

CLEAR_DISPLAY EQU F800:4BB1H

DWAD EQU F800:4BB1H

DBDTA EQU F800:4F1F

DEC_TEMP DB 0

SET_TEMP DB 0

ADC_VAL DB 0

COUNT DB 0

PRE_TEMP DB 0

.CODE

ADC TABLE:

DB 00H,03H,05H,08H,0aH,0dH,0fH,11H,14H,16H

DB 19H,1cH,1eH,21H,24H,27H,2aH,2cH,2eH,32H

DB 34H,36H,39H,3cH,3fH,42H,45H,48H,4aH,4cH

DB 4eH,50H,52H,54H,56H,58H,5bH,61H,64H,67H

DB 6aH,6dH,70H,72H,74H,77H,7aH,7dH,7fH,82H

DB a0H,a2H,a5H,a8H,aaH,aDH,afH,b0H,b3H,b6H

DB b9H,bcH,bfH,c1H,c4H,c6H,c9H,ccH,cfH,d0H

DB d2H,d5H,d7H,daH,dcH,dfH,e0H,e2H,e5H,e7H

DB e9H,ebH,eeH,f1H,f4H,f6H,f9H,fcH,ffH

START:

MOV AL,CTL_BYTE ; 8255

MOV DX,CTL ; PORTC (lower) as output

OUT DX,AL ; PORTA as input

MOV AL,DEC_TEMP

CALL DEC_HEX

MOV SET_TEMP,AL

MOV AL,DEC_TEMP

MOV AH,00

MOV SI,AX

CALL FAR DWAD

MOV DX,CTL

MOV AL,02

OUT DX,AL

MOV AL,00

OUT DX,AL

MOV CX,70

L0:

LOOP L0

BACK:

MOV COUNT,0

CALL ADC

CALL DISP_TEMP

CALL TEMP_CONTL

JMP BACK

DISP_TEMP:

MOV AL,ADC_VAL

MOV SI,OFFSET ADC_TABLE

AGAIN:

CMP AL,[SI]

JC FOUND

JE FOUND

INC SI

INC COUNT

JMP AGAIN

FOUND:

MOV AL,COUNT

CALL HEX_DEC

MOV AH,0

MOV SI,AX

CALL FAR DBDTA

RET

TEMP_CONTL:

MOV AL,COUNT

CMP AL,SET_TEMP

JC TURN_ON_RELAY

RELAY_OFF:

MOV DX,PORTB

MOV AL,0FFH

OUT DX,AL

MOV DL,20H

HERE1:

MOV CX,FFFFH

HERE:

LOOP HERE

DEC DL

JNZ HERE1

RET

TURN_ON_RELAY:

MOV DX,PORTB

MOV AL,00H

OUT DX,AL

CONTINUE:

MOV CX,FFFFH

L22:

LOOP L22

RET

ADC:

MOV DX,CTL

MOV AL,01

OUT DX,AL

MOV CX,70

L10:

LOOP L10

MOV AL,00

OUT DX,AL

L1:

MOV DX,PORTC

IN AL,DX

AND AL,80H

CMP AL,80H

JNZ L1

MOV DX,PORTA

IN AL,DX

MOV ADC_VAL,AL

RET

HEX_DEC:

MOV AH,00H

MOV CL,0AH

DIV CL

MOV CL,04H

ROL AL,CL

AND AL,F0H

OR AL,AH

RET

DEC_HEX:

MOV BL,AL

AND BL,0FH

AND AL,F0H

MOV CL,04

ROR AL,CL

MOV CL,0AH

MUL CL

ADD AL,BL

RET

END START

PROCEDURE:-

1. Connect power supply 5V & GND to both

microprocessor trainer kit & temperature controller interfacing kit.

2. Connect data bus between microprocessor trainer

kit & temperature controller interfacing kit.

3. Enter the program to read temperature of the

water bath from ADC at 0000:4000.

4. Execute the program by typing GO 0000:4000

enter.

5. Enter the reference temperature value, when

temperature of water bath exceeds reference value then power supply to water bath is

switched OFF.


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