netaji subhas institute of technology, new delhi - 8085...
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Netaji Subhas Institute of Technology,
New Delhi
Microprocessors Lab (EC-316)
CRICKET SCORE DISPLAY (MPU 8085 Project Report)
Under the supervision of
Prof. Dhananjay V.Gadre
DEPTT. OF ELECTRONICS AND COMMUNICATION
SUBMITTED BY:
Arnesh Majhi (34/EC/13)
Ashish kr yadav (38/EC/13)
ABSTRACT
Our accepted project was to design a cricket score display
using the 8085 microprocessor. Our designed device displays
the cricket score on the basis of information provided by a
Bluetooth connected android application. For the 8085
microprocessor to receive data from the Bluetooth module,
UART communication is used and the cricket score is then
shown on a LCD display.
The device fulfils the requirement of ardent cricket fans who
can watch the cricket score whenever they want without
compromising on their productivity.
The device that we plan to make is a prototype which will
receive information from an android application. In its fully
functional form it will be able to receive data straight from
the internet.
INDEX
ACKNOWLEDGEMENT
Firstly we would like to thank Prof Dhananjay Gadre for his
unconditional support and thorough guidance and initiative without
which this project would not have seen the light of the day.
We further express our gratitude for helping us at each stage of the
project. Furthermore we thank you for providing the necessary
components and access to facilities which enabled us to work
comfortably on our project.
We would also like to express our gratitude to the members of the
CEDT lab for their patience which played a major role in the successful
completion of our project.
Project Description
1) Why we made this?
The main application of MPUs is in fields where it is required that
human effort has to be minimized and to make the lives of human
beings simpler. This device is essential in a cricket crazy country
like India, as people cannot do without looking at a score. It is an
ideal product as it would be more convenient to look at a LCD
screen for the score as it would provide lesser room for
distractions, thus enhancing productivity.
Another use of this product is that when no matches are going on,
it can simply be used for displaying messages
2) How we made this?
In our project we interfaced a Bluetooth module (HC-05) with
serial-in and serial-out data pins of the 8085 MPU using resistors.
We then interfaced the 16x2 LCD display with the 8085 MPU
using 8255 peripheral device.
3) What we made?
COMPONENTS USED:
S.NO NAME OF COMPONENT QUANTITY
1. RESISTORS 14+ 1 trim-pot
2. CAPACITORS 14
3. 8085 1
4. 74HCT04(NOT GATE) 1
5. 74HCT573 1
6. 74138 (DECODER) 1
7. HC-05 Bluetooth Module 1
8. 8255 1
9. 32K ROM(28C256) 1
10. 32K RAM(62256) 1
11. RED LEDs 2
12. MINI USB PORT 1
13. PUSH BUTTONS 2
14. 16x2 LCD Display 1
In this project, a 4MHz quartz crystal and 3 jumpers have also been introduced for testing purposes
BLOCK DIAGRAM
SCHEMATIC
BOARD LAYOUT
The size of our board is 107.62 x 110.47mm
CODE LOGIC FLOWCHART
The size of the final program is 621 bytes.
PROJECT IMAGES
UNSOLDERED BOARD
BOARD DURING THE TESTING PHASE
EEPROM PROGRAMMER
TESTING AND DEBUGGING 1) Hardware Testing
2) Software Testing
1) Hardware Testing
Hardware testing is done prior to the software part. It is quite possible
that some of the hardware may be malfunctioning, hence they need to
be tested. The possible reasons for these problems could be:
a) Soldering may not be proper leading to formation of bubbles
b) Some of the ICs may be defective.
c) Accidentally, some track may have got damaged
d) While making the schematic, some connection may have been
missed out.
e) Switches may not be functioning properly or the LEDs could be
defective.
I) SID/SOD Test:
This is a basic test that helps to check the basic components like
ROM, clock, 8085 IC, latch 74573 and the decoding logic of the
circuit. In this test, a predefined code is uploaded to the ROM
such that the LED remains on until the switch is pressed.
If this test fails, then do the following-
Case 1: Press the reset button. The SOD LED should blink. If it
doesn’t, then either the reset button is not working properly or
the switch is not connected to the 8085. This can be checked
with the help of a multimeter. For checking switches,
connections and LEDs, connectivity mode must be used.
Case 2: Reset switch is working, but the LED doesn’t turn off
when the SID switch is on. Check the components and
connections using multimeter. Also check the voltage across
SID and SOD pin, they should be same.
II) LCD Test- The display device that we have used is a 16x2 LCD
display. When the system is reset and the LCD has been
initialized, then the backlight should be on and must display a
series of dark circles. If blocks are not visible, then the
potentiometer must be adjusted to change the contrast.
Now, a code which initializes the 8255 and displays some
ASCII characters is uploaded to the ROM. When the power
supply is turned on, ideally the LCD should display the
characters. If it doesn’t, the following could be the cause of the
problem-
a) LCD is defective
b) 8255 IC may be malfunctioning
c) Other miscellaneous problems like some track getting
damaged while working.
*8255 can be checked by sending a code to set the value of one
of the ports of the 8255 and verifying it with the help of a
multimeter.
III) Bluetooth testing- This aspect is the most crucial part of the
project. Under default conditions, HC-05 bluetooth module has a baud
rate of 9600 which indicates that the BT module is capable of
transmitting 9600 bits per second and it is sending 1 start bit, 1 stop bit
and 8 data bits. There are two methods of verifying this-
a) Using oscilloscope- In our circuit, we had introduced
jumpers which were removable so that SID SOD testing
circuit can be disabled from the circuit. So, now effectively,
we have our BT module connected to our SID pin and at
SOD pin, we now connect the oscilloscope probes. A
character is sent via Bluetooth module app in our mobile and
the waveform is captured on the oscilloscope. This fulfills
two purposes- it verifies that the data received by Bluetooth
is correct or not and whether the data is being interpreted
correctly by the 8085 MPU properly or not.
The above wave was formed when we transmitted the character ‘A’
through BT module which has an ASCII value of 41H and this can be
verified in the above waveform. It also shows that the time period of the
wave is 104us which proves that the BT module is operating at 9600
Baud.
b) Using AT command mode- In order to configure the default
settings or verifying the settings of the BT modules, one has
to use a Arduino Uno/ Nano to configure the settings
2) Software testing- There is no scientific technique to solve the
software errors. This can be done only by accurate calculation. In
this project, synchronizing the Bluetooth with the 8085 MPU was a
tedious and time consuming process which required a lot of
efficient and accurate calculations.
CONCLUSION
This project is working as expected. This implies that both
hardware and software components are working properly.
This project would not have been possible without the motivation
and guidance from Professor Dhananjay Gadre. Students from the
CEDT lab were also very helpful and supportive.
FUTURE APPLICATIONS The device that we have made is a general purpose device and
can be used for a wide range of applications such as wireless
notice board as well as applications such as message display.
BIBLIOGRAPHY
1) Microprocessor Architecture, Programming, and Applications with
the 8085 by Ramesh Gaonkar, Fifth edition, Penram International
Publishing. ISBN 81-87972-09-2 2) The 8085 Microprocessor: Architecture, Programming and
Interfacing by K. Udaya Kumar, Pearson Education India, 2008.
ISBN 978-81-7758-455-4
3) http://www.instructables.com/id/Modify-The-HC-05-Bluetooth-
Module-Defaults-Using-A/step3/Steps-To-Switch-The-HC-05-
Into-Command-Mode/
4) 8255 Datasheet:
http://www.alldatasheet.com/datasheetpdf/pdf/66100/INTEL/8255
A.html
5) Introduction to LCD Programming: http://www.8052.com/tutlcd