Ec2308 mini project

PRE-SETTABLE ALARM SYSTEM
ViniNarayanankutty (11509106086), SubhrataSarangi (11509106074), P.Sowmiya (11509106072)
N.Sindhuja (11509106070)
Department of Electronics communication & engineering
SRIRAM ENGINEERING COLLEGE, PERUMALPATTU

PROJECT REPORT
EC2308 Microprocessor and Microcontroller Lab
Guided By
Ms Philomena Jennifer
Lecturer, ECE
Date: 28/09/2011

ViniNarayanankutty (11509106086), SubhrataSarangi (11509106074), P.Sowmiya (11509106072) N.Sindhuja (11509106070)

ABSTRACT

Our Term Project is to study and implement a PRE-SETTABLE ALARM
SYSTEM using 8253/8254 timer and 8086 Microprocessor .We have
approached this design without using interrupts and it mainly involves the
use of thumbwheel switches which are interfaced through 8255 ports. The
alarm lasts for 5 seconds .The timing parameters are derived from
8253/54and control signals are generated using 74LS138.

EC2308 Microprocessors and Microcontrollers Page 2


ACKNOWLEDGEMENT

Our indebted thanks to our respected Dean Prof V.Thyagarajan, to do this project
work. We express our sincere thanks to our Head of the department, Mr.V.Salaiselvam
M.E. (PhD) who has helped us to take this invaluable project. We express our sincere
thanks to our guide Ms PHILOMENA JENNIFER, Lecturer ECE for the untiring
continued technical guidance during the fabrication and preparation of the Project. This is a
major motivation force for us to complete our project work.


SETTABLE

SRIRAM ENGINEERING COLLEGE
Perumalpattu, Thiruvallur Taluk - 602024
(Approved by AICTE, Affiliated to Anna University Chennai and Accredited by NBA)

REGISTER NO: 11509106086, 11509106074, 11509106072, 11509106070

MINI PROJECT REPORT
2011 – 2012
Name of lab: EC2308 MICROPROCESSOR AND MICROCONTROLLERS
8
Department: ELECTRONICS AND COMMUNICATION

Certified that this is a bonafide record of work done by VINI NARAYANANKUTTY, SUBHRATA
SARANGI, P.SOWMIYA,N.SINDHUJA Of 3RD YEAR 5TH SEMESTER Class, having completed the Mini
Project with his team members on the topic “PRE-SETTABLE ALARM SYSTEM SYSTEM”. In the
MICROPROCESSOR AND MICROCONTROLLER LAB during the year 2011 – 2012.

Submitted for the Demonstration held on: 28/09/2011
: 28

Signature of Head of dept: Signature of lab-in-charge:
lab charge:



TABLE OF CONTENTS

1. Introduction
1.1Design Description

2. Pre-settable Alarm System
2.1 Block diagram
2.2 Pin diagram and description
2.3 Signal specification
2.4 Address map
2.5 Control word formats

3. Program Coding

3.1 Coding
3.2 Delay Routine

4. Conclusion

4.1 Advantage of Pre-settable alarm system

5. References


ViniNarayanankutty (11509106086), SubhrataSarangi (11509106074), P.Sowmiya (11509106072) N.Sindhuja
(11509106070)

INTRODUCTION

An electronic alarm timepiece has a time counter, an alarm time memory
circuit and a coincidence detector for detecting a coincidence between the time
count and the stored alarm time for actuating an alarm. The alarm time memory
circuit is a pre-settable counter and it is pre-settable to load the present time count
in the time counter therein. In this way, a coarse adjustment of the alarm time can
be set and a manually operable mechanism is provided to increment the count in
the alarm time memory circuit to obtain the precise desired alarm time. There are
various types of alarm system available in the market.

1.1 Design Description

We go with design of simple pre-settable alarm system with alarm lasting for 5
seconds using 8253/54 timer and 8086 microprocessor without using interrupt. We
implement our design with thumbwheel switches to accept 4 digit values in
seconds. These switches are interfaced through 8255 ports. .A delay of 5 seconds is
provided in between each alarm by means of a delay routine.74LS138 decoder is
used to generate chip select signals for 8253/54 and 8255.One more 74LS138
decoder is used to generate , , and


(11509106070)


2.1 Block diagram


(11509106070)

2.2 Pin diagram and description

A. 8253/54

Clock This is the clock input for the counter. The counter is 16 bits. The maximum
clock frequency is 1 / 380 nanoseconds or 2.6 megahertz. The minimum clock
frequency is DC or static operation.

Out This single output line is the signal that is the final programmed output of the
device. Actual operation of the outline depends on how the device has been
programmed.

Gate This input can act as a gate for the clock input line, or it can act as a start
pulse, depending on the programmed mode of the counter.


(11509106070)


(11509106070)

B. 8255

1 D0 - D7 These are the data input/output lines for the device. All information
read from and written to the 8255 occurs via these 8 data lines.

2 (Chip Select Input). If this line is a logical 0, the microprocessor can read
and write to the 8255.

3 (Read Input): whenever this input line is a logical 0 and the RD input is
a logical 0, the 8255 data outputs are enabled onto the system data bus.

4 (Write Input) Whenever this input line is a logical 0 and the CS input is
a logical 0, data is written to the 8255 from the system data bus

5 A0 - A1 (Address Inputs): The logical combination of these two input lines
determines which internal register of the 8255 data is written to or read
from.

6 RESET The 8255 is placed into its reset state if this input line is a logical 1.
All peripheral ports are set to the input mode.


(11509106070)

7 PA0 - PA7, PB0 - PB7, and PC0 - PC7: These signal lines are used as 8-bit
I/O ports. They can be connected to peripheral devices.

2.3 Signal specification

The figure shows interfacing of 8253/54 with 8086 with 16-bit address.

Here and signals are activated when M/ signal is low,
indicating I/O Bus cycle. To get absolute address, all remaining address lines (A3-
A15) are used to decode the address for it. In order to access it we must use
indirect addressing modes


(11509106070)

2.4 Address map

The address map shows how addresses have been allocated for memory
and any other devices connected to the address bus.

Ports/Control Register Address lines Address

A7 A6 A5 A4 A3 A2 A1 A0

Counter 0 0 0 0 0 0 0 0 0 00H
Counter 1 0 0 0 0 0 0 1 0 02H
Counter 2 0 0 0 0 0 1 0 0 04H
Control register 0 0 0 0 0 1 1 0 06H
Port A 0 0 0 0 1 0 0 0 08H
Port B 0 0 0 0 1 0 1 0 0AH
Port C 0 0 0 0 1 1 0 0 0CH
Control register 0 0 0 0 1 1 1 0 0EH


(11509106070)

2.5 Control Word Format

1. Control word to Read/write value in count register of counter 0 of 8253/54
D7 D6 D5 D4 D3 D2 D1 D0
SC1 SC2 RW1 RW0 M2 M1 M0 BCD
0 0 1 1 0 0 0 1

Control word =31H
D0=1 ; BCD count
D3, D4, D5=000; Mode: interrupt on terminal count
D5, D4=11 ; Read/write lower byte first and then higher byte
D7, D6=00 ; Counter 0

2. Control word to Read/write value in count register of counter 1 of 8253/54

D7 D6 D5 D4 D3 D2 D1 D0
0 1 1 1 0 1 1 1

Control word =77H
D0=1 ; BCD count
D3, D4, D5=011; Mode: Square Wave Rate Generator
D5, D4=11 ; Read/write lower byte first and then higher byte


(11509106070)

3. Control word to latch value in count register of counter 0 of 8253/54

D7 D6 D5 D4 D3 D2 D1 D0
0 0 0 0 0 0 0 1

Control word =01H
D0=1 ; BCD count
D5, D4=00 ; Counter latch command


D7 D6 D5 D4 D3 D2 D1 D0
1 0 0 0 0 0 0 1

Control word =81H
D0=1 ; BCD count
D5, D4=11 ; Counter latch command


(11509106070)


D7 D6 D5 D4 D3 D2 D1 D0
1 0 1 1 0 0 0 1

Control word =B1H
D0=1 ; BCD count
D5, D4=11 ; Read back command in 8254

5. Control word to INITIALISE 8255:

BSR/IO MODE A PA PCH MODE B PB PCL
1 0 0 1 0 0 1 0

Control word =92H
BSR/IO=1 ; IO Mode
MODE A=00; Mode0
PA=1; Port A=simple input
PCH=0, PCL=0; Port C=simple output
PB=1; Port B=simple input


(11509106070)

3. PROGRAM CODING

3.1 Main Program Coding

MOV AL, 92H; Load control word in accumulator
OUT 0EH, AL; Initialize 8255 by sending control word at the addresses of
Control register
START: IN AL, 08H; Get the lower two digit of count
MOV BL, AL; Store the lower two digit of the count
IN AL, 0AH; Get the higher two digit of count
MOV BH, AL; Store the higher two digit of the count
MOV AL, 31H
OUT 06, AL; Load control word (31H) in the control register to load 16-bit
Count in count register of counter 0
MOV AL, BL
OUT 00, AL; Loads lower byte of the count
MOV AL, BH
OUT 00, AL; Loads higher byte of the count
BACK MOV AL, 01H;
BACK:
OUT 06, AL; Load control word (01H) in the control register to load 16-bit
Count in count register of counter 0
IN AL, 00H; Get the lower two digit of count
CMP AL, 00H; Compare with zero
JNZ BACK; Repeat
IN AL, 00H; Get the higher two digit of count
JNZ BACK; Repeat
BACK;
MOV AL, 01H; Load bit pattern to run alarm
OUT 0CH, AL; send it to Port C
CALL DELAY; Wait for 5 seconds
MOV AL, 00H; Load bit pattern to stop alarm
OUT 0CH, AL; send it to Port C
JMP START; Repeat
START;

3.2 Delay Routine


(11509106070)

This delay routine gives a delay of 5 seconds. Counter 1 of 8253/54 is
used to give delay of 1 second. As output of counter1 is used as a clock for
counter2, the count in the counter2 acts as a multiplying factor. Therefore,
by loading 05H in the count register of counter 2 we get a delay of (5×1)
seconds.

MOV AL, 77H
OUT 06, AL; Loads control word (71H) in the control register
MOV AL, 10H
OUT 02, AL
MOV AL, 27H
OUT 02H
MOV AL, B1H
OUT 06H, AL
MOV AL, 05H
OUT 04, AL; Loads lower byte of the count
MOV AL, 00H; Loads higher byte of the count
OUT 04, AL
BACK MOV AL, 81H
BACK:
OUT 06, AL; Loads control word (81H) in the control register to latch
16-bit count in the count registers of counter 2
IN AL, 04H; Get lower two digits of the count
JNZ BACK If not zero, repeat
BACK:
IN AL, 04H; Get the higher two digits of the count

JNZ BACK If not zero, repeat
BACK:
RET; Return to main program


(11509106070)

4. CONCLUSION

4.1 Advantages

1. Simple to design.
2. Reduces the need of using Schmitt –trigger NAND gate usually used in
alarms.

5. REFERENCES

1 Pre-settable alarm clock-Wikipedia.
2 www.seminarprojects.com
3 Microprocessors and interfacing: Programming and hardware
Douglas V. Hall


Ec2308 mini project

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Ec2308 mini project

Similar to Ec2308 mini project (20)

Recently uploaded

Recently uploaded (20)

Ec2308 mini project