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Table of Contents
CHAPTER 1...............................................................................................................................2
INTRODUCTION..................................................................................................................2
1.1 PROJECT BACKGROUD......................................................................................2
1.2 PROBLEM STATEMENT......................................................................................4
1.3 OBJECTIVES..........................................................................................................5
1.4 SCOPE.....................................................................................................................6
CHAPTER 2...............................................................................................................................7
LITERATURE REVIEW.......................................................................................................7
2.1 WHY USE PIC16F877A.........................................................................................7
2.2 WHY USE ULTRASONIC SENSOR HC - SR04..................................................8
2.3 WHY USE LCD-DS-LCD-162A............................................................................9
CHAPTER 3.............................................................................................................................10
METHODOLOGY...............................................................................................................10
3.1 WORK PROGRESS FLOW..................................................................................10
3.2 METHODS (PROGRAM USED).........................................................................11
3.3 HARDWARE DEVELOPMENT..........................................................................16
3.4 SOFTWARE DEVELOPMENT...........................................................................21
CHAPTER 4.............................................................................................................................29
RESULT AND ANALYSIS:...............................................................................................29
CHAPTER 535 COST EVALUATION…………………………………………………………………….355.1..................BILLS OF MATERIALS AND COMPONENTS……………………………….35
5.2 OVERALL PROTOTYPE PRICE……………………………………………….36
CHAPTER 6………………………………………………………………………………….37
CONCLUSION....................................................................................................................37
6.1 RECOMMENDATION..............................................................................................38
REFERENCES.........................................................................................................................40
APPENDICES..........................................................................................................................41
2
CHAPTER 1
INTRODUCTION
1.1 PROJECT BACKGROUD
For this project, ‘Digital Car's Fuel Detector’ has been picked as the main application
regarding the ultrasonic sensors. This is due to the aspects that the technology can be used for
measuring wind speed and direction (anemometer), tank or channel level, and speed through
air or water. This ultrasonic criterion perfectly fixes the need of sensor to detect the fuels
level in the car tank. When measuring the tank or channel level, the sensor measures the
distance to the surface of the fluid.
Ultrasonic sensors work on a principle which evaluates attributes of a target by
interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors functioned
particularly similar to radar or sonar. Besides that, it is also known as transceiver where they
both transmit and receive signal. Ultrasonic sensors generate high frequency sound waves
and evaluate the echo which is received back by the sensor. Sensors calculate the time
interval between sending the signal and receiving the echo to determine the distance to an
object. The illustration on how the ultrasonic sensor works based on its wave propagated is
shown in Figure 1 and Figure 2. When the wave is propagated back the time taken is recorded
and produced by the ultrasonic to be inserted in the calculation below to obtain the exact
distance travelled by the wave.
Distance ¿object=T × speed of sound2
T = time between when an ultrasonic wave is emitted and when it is received Division by 2 is
because the sound wave has to travel to the object and back.
3
Figure 1: wave is transmitted and reflected back
Figure 2 : the distance is determined based on time elapsed
This principle is being used to detect the indicator in the container and display back the value
of the remaining fuel in the tank. This application is suitable with the project as the sensor is
also propagated its wave and will always remind the user about the fuel level in the tank.
4
1.2 PROBLEM STATEMENT
This project acts as an effort to overcome the running out of the fuel in the vehicles’
fuel tanks. ‘Digital Car's Fuel Detector’ is invented to detect the fuel level in the car tank as
the input and the percentage of the tank from its full capacity will be displayed on the LCD
screen. This eventually should ease the user to estimate the fuel that they need to have for
their journey. At the same time this type of product will save the fuel from being wasted and
in another way consume the cost of the user itself. As for now it may seem useless but this
product is somehow will benefits the user in the future as the value of fuel is unstable and that
will affect the amount that we used every day as it will not be the same as before.
5
1.3 OBJECTIVES
1. To design a digital fuel detector for cars which is assembly based program using PIC.
2. To implement the function of ultrasonic sensor to detect the level of the fluid in the
tank.
3. To develop a digital fuel detector that is able to show car’s fuel percentage on LCD
screen as the output.
6
1.4 SCOPE
The scope of the project has been narrowed to specific functions and capabilities. The
proposed title for the project capped around few limitations. The project is based on
Programmable Integrated Circuit PIC 16F877A where LCD screen and ultrasonic sensor will
be equipped together. The chosen PIC is used since the course for “Microprocessor and
Microcontroller” only covers PIC16 areas. Besides that, PIC16 is a widely used
microcontroller and its instruction set, tutorials and examples are easy available especially on
the internet.
This fuel tanks detector is suitable to be applied on anything that used a covered top
container or oblique material tank where the quantity or volume inside it cannot be seen
through from the outside. For this project, a fuel tank such as vehicles is used as an
inspiration to this idea, where the detector will display how many percentage of the material
inside it has being used. Therefore, the customer scope of this project mainly focusing on
people with vehicles such as motors, cars, lorries and others.
An LCD display which is one of the products of Cytron Technologies model DS-
LCD-162A will be used as a display output device. The LCD display also is widely used in
electronic projects and easily available at any electronic stores. The sensor that will be used
are limited to Ultrasonic sensor which also a Cytron Technologies product model HC-SR04.
These are the sensor that will be used in the project to sense the fuel’s level in a container.
Some of applications can be used for light or heavy usage. Robust Digital Fuel Level
is Sensor is an example which is suitable for standard and heavy application. The project that
will be built are more to standard use since the system are expected will be running with low
5V DC power supply. At the end of the project, the location involved for testing the project
only in Universiti Tun Hussein Onn Malaysia (UTHM) Batu Pahat, Johor and nearby area.
7
CHAPTER 2
LITERATURE REVIEW
2.1 WHY USE PIC16F877A
For years, ultrasonic sensors have been used in a wide range of applications including
fish finders, parking sensors in cars and burglar alarms. There are some others
ultrasonic application of ultrasonic sensor that can benefits the mankind. These are
some of the important review regarding of the Digital Car’s Fuel Detector.
Figure 3 : Microcontroller of PIC16F877A
A microcontroller is a compact microcomputer designed to govern the operation of
embedded systems in motor vehicles, robots, office machines, complex medical
devices, mobile radio transceivers, vending machines, home appliances, and various
other devices. A typical microcontroller includes a processor, memory, and
peripherals. As for this project microcontroller of PIC16F877A is used. This PIC acts
as the brain of this project as it will conduct what particular components action during
the particular time.
8
2.2 WHY USE ULTRASONIC SENSOR HC - SR04.
Figure 4 : Ultrasonic sensor of HC - SR04.
Ultrasonic sensor comes from two different words, which are ultrasonic (ultrasound)
and sensor. Ultrasound is an acoustic wave with a very high frequency, beyond
human hearing. Since the audible frequency range is said to be between 20Hz and 20
kHz, ultrasound generally means acoustic waves above 20 kHz. Bats, with their echo-
location (biological ultrasonic radar), can hear sounds up to 200 kHz, way above the
capabilities of the human ear. Whereas sensor can be define as a device that detects
and responds to some type of input from the physical environment. The specific input
could be light, heat, motion, moisture, pressure, or any one of a great number of other
environmental phenomena.
Ultrasonic ranging module HC - SR04 is used as the input in this project as it
provides 2cm - 400cm non-contact measurement function, the ranging accuracy can
reach to 3mm. The modules includes ultrasonic transmitters, receiver and control
circuit.
9
2.3 WHY USE LCD-DS-LCD-162A.
Figure 5 : Liquid Crystal Display of LCD-DS-LCD-162A.
LCD (liquid crystal display) is the technology used for displays in notebook and other
smaller computers. LCD also comes as a separate component which is portable and
suitable to be used in all electrical projects that needs a display as the output. A
specific LCD is picked to display the output for this project, which is LCD-DS-LCD-
162A.
10
CHAPTER 3
METHODOLOGY
3.1 WORK PROGRESS FLOW
11
Figure 6 : The progress flowchart
3.2 METHODS (PROGRAM USED)
Throughout the process of making the project prototype, a number of methods are
used to make the project prototype complete successfully. In a group with four members,
individual skills such as circuit designing, soldering and prototype modelling on each group
members are shown during the process of making the prototype. As for technical part, the
main circuit and power supply circuit are designed by using Proteus 7.8 software.
Applications such as ISIS Professional 7 and ARES Professional 7 are provided by Proteus
12
7.8. ISIS Professional 7 is used for circuit schematic designing and analyzing purposes while
ARES Professional 7 is used for designing printed circuit board layout. The body of the
prototype are made from scratch by using unused polystyrene blocks, plastic board and
unused bottle flask. As the conclusion the software that is being used to accomplished this
project are:
1. Proteus Professional 7.8
2. ARES Professional 7
3. ISIS Professional 7
4. MPLAB IDE
13
3.2.1 Proteus Professional 7.8
Figure 3.2.1: Proteus 7.8 software loading screen
Proteus Professional 7.8 is an application framework that enables users to edit current
schematic or design files also with creating a new one between schematic and PCB. The
Proteus Professional 7.8 is casually intended for prospective customers who wish to evaluate
professional level products. It differs from Proteus Lite or other kind of free circuit schematic
designer where it does not allow users to save, print or design their own microcontroller
based, electronics and electric circuit. Proteus Professional 7.8 does include all features
offered by the other professional system including net list based PCB design with auto-
placement, auto-routing and graph based simulation. The Proteus Design Suite combines
schematic capture, SPICE circuit simulation, and PCB design to make a complete electronics
design system. Throughout of project process, two of Proteus Professional 7.8 applications
used are ARES Professional 7 and ISIS Professional 7.
14
3.2.2 ARES Professional 7:
Figure 3.2.2: ARES Professional 7 application icon
ARES Professional 7[1] is a high performance net list based PCB design packages
where is it perfectly complements with their ISIS schematic capture software. Any schematic
circuit designed can be easily converted into PCB layout. Auto router and components auto
placer tools are provided for easy components placing and copper routing. Other than that,
options such as copper route size and wire grid size can be adjusted according to user’s
choice.
3.2.3 ISIS Professional 7:
Figure 3.2.3: ISIS Professional application icon
ISIS [2] one of the main part in Proteus system, and is far more advance than just
another schematics package. It combines a powerful design environment with the ability to
define most aspects of the drawing appearance. Flexible schematic designing with various
lists of components such as resistors, sensors, LCDs, capacitors and many more are granted
by ISIS. The flexibility of circuit designing comes when components and wires can be easily
dragged and dropped onto the schematic workspace. Assembly program are uploaded into
this application for circuit simulation.
15
3.2.4 MPLAB IDE
MPLAB IDE software are produced by Microchip Company and it is used to write
assembly language program. Since the project program are written is assembly language, any
process related with assembly programming such as writing assembly codes, program
executing and debugging are done by using MPLAB IDE software. Microchip has a large
suite of software and hardware development tools integrated within one software package.
MPLAB IDE is a free, integrated toolset for the development of embedded applications on
Microchip's PIC and dsPIC microcontrollers. It is called an Integrated Development
Environment (IDE) as it provides a single integrated environment to develop code for
embedded microcontrollers.
Figure 3.2.4.1: Microchip MPLAB IDE log
MPLAB IDE are easy to be used and a host of free software components are included
for fast application development and debugging. MPLAB IDE are served as single, unified
graphical user interface for additional Microchip and third party software and hardware
development tools. Assembler, debugger, editor, project manager and execution engines are
the main components of MPLAB IDE.
16
Figure3.2.4.2: Some of MPLAB IDE components
The project manager provides integration and communication between the IDE and
the language tools. The editor is a full-featured programmer's text editor that also serves as a
window into the debugger. The assembler can be used stand-alone to assemble a single file,
or can be used with the linker to build a project from separate source files, libraries and
recompiled objects. The linker is responsible for positioning the compiled code into memory
areas of the target microcontroller. The Microchip debugger allows breakpoints, single
stepping, watch windows and all the features of a modern debugger for the MPLAB IDE. It
works in conjunction with the editor to reference information from the target being debugged
back to the source code. There are software simulators in MPLAB IDE for all PICmicro
MCU and dsPIC DSC devices. These simulators use the PC to simulate the instructions and
some peripheral functions of the PICmicro MCU and dsPIC DSC devices. Optional in-circuit
emulators and in-circuit debuggers are also available to test code as it runs in the applications
hardware [3].
17
3.3 HARDWARE DEVELOPMENT
POWER SOURCE
To make a controller function, a power source of 5V is needed to power up the PIC.
Therefore, a 5VDC power supply is built up using the current from the power adapter. Power
adapter is chosen to replace the transformer function. This is because of the safety reason and
materials expenditures. When an adapter is used as a power source to generate 5V power
supply, the probability of the circuit to damage or exploded is decreases as power adapter is
more reliable than the transformer that is known as its complication to stable the
performance. Beside that the expenditures that need to be calculated when a transformer
exploded is much higher whereas an adapter seldom undergone such problem. Figure 9 is the
power source circuit that has been tested and worked properly.
Figure 7 : Schematic diagram of power source
18
Figure 8 : Power source circuit board
Figure 9 : The circuit tested
19
LCD
In this project, the most commonly used character based LCD, which is based on
Hitachi’s HD44780 controller, has been used. The HD44780 standard requires 3 control lines
as well as 8 I/O lines for the data bus for the 8-bit LCD interface. For an 8-bit data bus, it will
require a total of 11 data lines (3 control lines plus the 8 lines for the data bus). The data bus
consists of 8 lines. In the case of an 8-bit data bus, the lines are referred to as
DB0, DB1, DB2, DB3, DB4, DB5, DB6, and DB7. The three control lines are referred to
as EN, RS, and RW.
The EN line is called “Enable.” This control line is used to instruct the LCD that the
data is sending to it. Initially, this line is low (0) and then set the other two control lines
and/or put data on the data bus. When the other lines are completely ready, bring EN high (1)
and wait for the minimum amount of time required by the LCD datasheet, and end by
bringing it low (0) again.
Next, the RS line is the “Register Select” line. When RS is low (0), the data is to be
treated as a command or special instruction, such as clear screen and position cursor. When
RS is high (1), the data being sent is text data which should be displayed on the screen. For
example, to display the letter “S” on the screen the RS line has been set high. Lastly,
the RW line is the “Read/Write” control line. When RW is low (0), the information on the
data bus is being written to the LCD. When RW is high (1), the program is effectively or
reading the LCD.
20
Pin No. Name Description
1 Vss Power Supply (GND)
2 Vcc Power Supply (+5V)
3 Vee Contrast Adjust
4 RS 0 = Instruction Input
1 = Data Input
5 R/W 0 = Write to LCD Module
1 = Read from LCD Module
6 EN Enable Signal
7 DB0 Data bus line 0 (LSB)
8 DB1 Data bus line 1
9 DB2 Data bus line 2
10 DB3 Data bus line 3
11 DB4 Data bus line 4
12 DB5 Data bus line 5
13 DB6 Data bus line 6
14 DB7 Data bus line 7 (MSB)
Table 1: The character of the LCD pins
Figure 10: The LCD circuit connection
21
ULTRASONIC SENSOR
The sensor has two opening on its front; one opening emits ultrasonic waves, while the other
receives them. The ultrasonic Sensor measures the distance by timing how long it takes for an
ultrasonic wave sent out by the emitter to bounce off an object and come back to the receiver.
The speed of the sound is approximately 341m/s in air. The sensor uses this information,
along with the time difference between sending and receiving the sound pulse, to determine
distance to an object using this equation:
Figure 11 : HC-SR04 Ultrasonic sensor on the breadboard
Distance ¿object=T × speed of sound2
T = time between when an ultrasonic wave is emitted and when it is received Division by 2 is
because the sound wave has to travel to the object and back.
22
3.4 SOFTWARE DEVELOPMENT
The Figure 12 shows the overall view on how the program should work. Whereas the Figure2
until Figure19 is how the LCD program is being generated in the PIC itself. Lastly, the
Figure20 and Figure21 describe the flow of the ultrasonic sensor in the program.
Figure 12 : Program flowchart
23
LCD INTERFACE:
24
Figure 13: Flow chart of the assembly code for the LCD interface (main)
Figure 14 : Flow chart of the assembly code for the LCD interface (initialisation)
25
Figure 15 : Flow chart of the assembly code for the LCD interface (M1 subroutine)
Figure 16 : Flow chart of the assembly code for the LCD interface (LINEA2 subroutine)
26
Figure 17 : Flow chart of the assembly code for the LCD interface (M2 subroutine)
Figure 18 : Flowchart of the assembly code for the LCD interface (continue)
27
Figure 19 : Flow chart of the assembly code for the LCD interface (continue)
28
ULTRASONIC SENSOR INTERFACE:
Figure 20 : Ultrasonic interface flowchart_1
29
Figure 21 : Ultrasonic flowchart_2
30
CHAPTER 4
RESULT AND ANALYSIS:
Before the controller part is being developed, the power source that needed to power up the
PIC is being built and tested. The ideal voltage that needs to be produced by the power source
circuit in order to operate the PIC is 5V. Analysing of circuits is done by using 2 methods
which are by using ISIS Professional 7 application and testing with multimeter. Before PCB
being printed out, the designed circuit are tested on breadboard for functionality test. Both
power supply circuit and main application circuit are tested by using this method. Voltage
flow in the circuit is measured by using ISIS and multimeter. Figure 22 is the result when the
power source circuit is being testes\d, the value of the output is exactly 5V.
Figure 22: Power supply output voltage analysis at 5V
31
In order to retrieve the result, the PIC16F877A microcontroller at the schematic circuit in the
Proteus software has been edited by selecting the .HEX program file of the assembly codes
that has been built previously. After the schematic circuit has been simulated with the
assembly codes generated in the PIC16F877A, the output display has shown “SALAM
DR.SHAMIAN” strings, based on Figure 23.
Figure 23: The window view for editing the component of PIC16F877A
Figure 24: The output display on the schematic circuit
Finally, the assembly code has been downloaded into the PIC16F877A and the output display
has been produced as shown in Figure 24. This is the step where the LCD is has been
successfully configured and tested by a simple program without the interference of the
ultrasonic sensor.
32
Figure 25: The output display on LCD screen
The interfacing of HC-SR04 Ultrasonic sensor with PIC16F877A has successfully displaying
measurement of an object. The measurement displayed on the LCD is a little bit different
from the measurement obtained by using ruler.
Figure 26: Object at a distance of 18 cm from the HC-SR04 Ultrasonic sensor.
33
Figure 27: Top view of an object at a distance of 18 cm from the HC-SR04 Ultrasonic sensor
Figure 28: Measurement LCD-display
Measurement displayed on the LCD when an object is at 18.5 cm of distance away from the
HC-SR04 Ultrasonic sensor as shown in Figure 27. The distance displayed is changed
sometimes to 18.0 cm, 19.0 cm and more when a little disturbance applied on the measured
object. Uncertainty of +- 5 cm of measurement displayed are obtained when the object being
measured. Lastly, the circuit is being assembly on the prototype that has been build up to
show the function of the project itself. The ultrasonic sensor will be placed at the bottom of
the water container’s cover like shown in Figure 28. The cover will be placed on the
prototype later on. From Figure 29 the connection from the breadboard to the ultrasonic
sensor can be seen. As the prototype is placed and functioning the result of the output as in
Figure 30 will be displayed on the LCD.
34
Figure 29: Ultrasonic sensor
Figure 30: Circuit connection
35
Figure 31: LCD Display
36
CHAPTER 5
COST EVALUATION
5.1 BILLS OF MATERIALS AND COMPONENTS
Power Supply
No. Items Quantity Price for Each Unit (RM) Total Price (RM)1. IC 7805 Voltage Regulator 1 2.00 2.002. Ceramic Capacitor 100 µF 2 0.65 1.303. Ceramic Capacitor 0.01 µF 2 0.15 0.304. Resistor 220 Ω 1 0.05 0.055. 1N4007 1 0.20 0.206. Light Emitting Diode (LED) 1 0.40 0.407. 2 Pin Terminal Block 2 1.20 2.408. DC Jack 1 2.00 2.009. DC Power Adapter (Variable) 1 18.00 18.0010. Printed Circuit Board 1 * *
Overall Price (RM) 26.65*Components/materials are obtained from laboratory
Table 2: Bills of materials and components for 5V power supply circuit
Main Circuit
No. Items Quantity Price of Each Unit (RM) Total Price (RM)1. 16X2A LCD 1 18.00 18.002. Potentiometer 5k Ω 1 1.20 1.203. PIC16F877A 1 17.00 17.004. Jumpers 1 12.00 12.005. 4 MHz Crystal Oscillator 1 2.00 2.006. 22 pF Ceramic Capacitor 2 0.15 0.307. 40-Pin IC Socket 1 0.70 0.708. Straight 2mm Female Header 1x40 Ways 2 1.20 2.409. HC-SR04 Ultrasonic Sensor 1 39.00 39.0010. Printed Circuit Board 1 * *
Overall Price (RM) 92.60*Components/materials are obtained from laboratory
Table 3: Bills of materials and components for main circuit
37
Prototype
No. Items Quantity Price of Each Unit (RM) Total Price (RM)1. Plastic Board 1 4.00 4.002. Polystyrene Blocks 1 * *3. Water Flask 1 4.00 4.004. Small Screws 8 0.05 0.40
Overall Price (RM) 8.40*Components/materials are obtained unused items
Table 4: Bills of materials and components for prototype
.
5.2 OVERALL PROTOTYPE PRICE
The overall price for the whole prototype is the sum total price for power supply circuit, main
circuit and prototype. The calculation of the product’s price are shown in the calculation
below:
A=Overall Price for Power Supply CircuitB=Overall price for MainCircuit
C=Overall price for Prototype
Produc t' s Price=A+B+CProduc t' s Price=RM 26.65+RM 92.60+RM 8.40
Produc t' s Price=RM 127.65
38
CHAPTER 6
CONCLUSION
As a conclusion, a prototype of ‘Digital fuel tank detector’ is successfully developed. This
prototype used an ultrasonic sensor as it input and the output will be displayed at LCD
display. Throughout this project, the LCD display is managed to display the output where the
percentage of the fuel tank is being calculated and the ultrasonic sensor is able to detect the
obstacle that is in it range. Most important is that, the PIC is successfully configured and all
the error is fixed in order to achieve all the objectives and to come out with a fully working
prototype.
39
6.1 RECOMMENDATION
Although this project has been successfully build with its application. There is still space to
improve this project. This recommendation is made up based on the suitability for this
product to be marketed in the future. This idea can be manipulated to produce a product that
can be commercialized in order to improve the lifestyle of human being in this modern-
technologies world. These are some of the recommendation that is suggested for further
improvement:
1. Modified the application.
Besides fuel tank, this project can be modified to use in other environment, such as a
detector to alert the user if the water tank is almost run out of water. This is quite
useful as the main water tank is at the rooftop. It is difficult if the user need to check
the water tank regularly especially to some places than undergoes water restriction.
This will ease the user to be in a standby mode if the water ran out.
2. Use M-Series Fuel Level Sensors from Gill Sensors.
Figure 32: M-Series fuel level sensor
M-Series fuel level sensors are custom designed using capacitive technology; the
sensors have no moving parts and are extremely accurate. They can be designed to fit
40
within the tightest of space envelopes and withstand the harshest of environments.
This type of sensors has a few additional characteristic make it the best sensor to
replace the ultrasonic sensor for the application regarding fuel.
These sensors are compatible with all petroleum/gasoline fuels and are offered with
totally configurable outputs and onboard multiple fuel calibration functions. The
additional characteristics are:
i. Fully immersible
ii. Custom designed to specific requirements
iii. Super –lightweight versions available
41
REFERENCES
[1] http://www.labcenter.com/products/pcb/pcb_intro.cfm. Retrieved on 19th May 2014.
[2] http://www.labcenter.com/products/pcb/schematic_intro.cfm. Retrieved on 19th May
2014.
[3] http://www.element14.com/community/docs/DOC-39318/l/microchip-mplab-
integrated-development-environment-ide-overview. 11th November 2011 by Ankur
Tomar. Retrieved on 18th May 2014.
[4] http://tutorial.cytron.com.my/2012/02/04/lcd-interfacing-with-pic-microcontrollers-
part-1/ . Retrieved on 20/3/2014.
[5] http://tutorial.cytron.com.my/2012/03/14/lcd-interfacing-with-pic-microcontrollers-
part-2/ .Retrieved on 20/3/ 2014.
[6] http://www.pyroelectro.com/tutorials/pic_lcd/software.html (retrieved on 21/3/2014).
[7] http://www.datasheetarchive.com/lcd%20162A-datasheet.html (retrieved on
21/3/2014).
[8] http://www.circuitstoday.com/interfacing-16x2-lcd-with-8051 (retrieved on
21/3/2014).
[9] Azosensor, 200-2014, Retrieved at http://www.azosensors.com/equipment-
details.aspx?EquipID=271
[10] Sapcon Instrument, FLY ASH Level Detection in ESP Hoppers, 2013.
Retrieved at http://www.sapconinstruments.com/articles.
[11] Datasheet, Retrieved at http://www.datasheetarchive.com/lcd%20162A-
datasheet.html
[12] Interfacing LCD, Retrieved at http://www.circuitstoday.com/interfacing-16x2-
lcd-with-8051
42
APPENDICES
LCD INTERFACE
;########################################################################
LIST P=16F877A
INCLUDE "P16F877A.INC"
ERRORLEVEL 0,-302
__CONFIG 0X3F32
;########################################################################
CBLOCK 0X20
LCOUNT
HCOUNT
Timer1
ENDC
;########################################################################
ORG 00h ; Started at address 0
GOTO MAIN ; Jumps to MAIN
ORG 5
;########################################################################
M1:
MOVLW 'S'
MOVWF PORTD
CALL ENVIA
MOVLW 'A'
MOVWF PORTD
CALL ENVIA
MOVLW 'L'
43
MOVWF PORTD
CALL ENVIA
MOVLW 'A'
MOVWF PORTD
CALL ENVIA
MOVLW 'M'
MOVWF PORTD
CALL ENVIA
RETURN
M2:
MOVLW 'D'
MOVWF PORTD
CALL ENVIA
MOVLW 'R'
MOVWF PORTD
CALL ENVIA
MOVLW '.'
MOVWF PORTD
CALL ENVIA
MOVLW 'S'
MOVWF PORTD
CALL ENVIA
MOVLW 'H'
MOVWF PORTD
CALL ENVIA
MOVLW 'A'
MOVWF PORTD
CALL ENVIA
44
MOVLW 'M'
MOVWF PORTD
CALL ENVIA
MOVLW 'I'
MOVWF PORTD
CALL ENVIA
MOVLW 'A'
MOVWF PORTD
CALL ENVIA
MOVLW 'N'
MOVWF PORTD
CALL ENVIA
RETURN
Onems
MOVLW D'249'
MOVWF Timer1
Loop1
DECFSZ Timer1,F
GOTO Loop1
RETURN
INITIAL_LCD:
BCF PORTB,6 ; Set RS=0
MOVLW 0x01 ; Set D0=1, the command control code is '00000001'
MOVWF PORTD ; Therefore it clears screen
CALL COMMAND ; Jumps to COMMAND
MOVLW 0x0C ;
45
MOVWF PORTD
CALL COMMAND ;
MOVLW 0x3C ;
MOVWF PORTD
CALL COMMAND ;
BSF PORTB,6 ;
RETURN
COMMAND:
BSF PORTB,7 ; Enable pin is set
CALL DELAY ; Jumps to DELAY
CALL DELAY ; Jumps to DELAY
BCF PORTB,7 ; Enable pin is clear
CALL DELAY ; Jumps to DELAY
RETURN
ENVIA:
BSF PORTB,6 ;
CALL COMMAND ;
RETURN
LINEA2:
BCF PORTB, 6 ; RS=0
MOVLW 0xC0 ;
MOVWF PORTD
CALL COMMAND ; Jumps to COMANDO
RETURN
DELAY:
46
MOVLW 0xFF
MOVWF LCOUNT
MOVLW 0xFF
MOVWF HCOUNT
DELAY_LOOP:
DECFSZ LCOUNT,1
GOTO DELAY_LOOP
DECFSZ HCOUNT,1
GOTO DELAY_LOOP
RETURN
MAIN:
BSF STATUS,RP0
BCF STATUS,RP1
CLRF TRISB
CLRF TRISD
BCF STATUS,RP0
CLRF PORTB
CLRF PORTD
START_LCD:
CALL INITIAL_LCD
CALL M1
CALL LINEA2
CALL M2
NOP
GOTO $-1
END
47
THE FULL PROTOTYPE SOURCE CODE
LIST P=16f877a
INCLUDE "P16F877A.INC"
ERRORLEVEL 0,-302
__CONFIG 0X3F32
;****************************************************************
CBLOCK 0X20 ; Start of general purpose registers
LCOUNT
HCOUNT
TIME1
TIME2
ONE
TEN
HUNDRED
TIMES
VALUE
DEC_POINT
COUNTER
STORE
ENDC
;****************************************************************
ORG 0X00
GOTO MAIN
;****************************************************************
DELAY MOVLW 0XAF
MOVWF LCOUNT
48
MOVWF HCOUNT
DELAY_LOOP DECFSZ LCOUNT,F
GOTO DELAY_LOOP
MOVLW 0XAF
MOVWF LCOUNT
DECFSZ HCOUNT,F
GOTO DELAY_LOOP
RETURN
;****************************************************************
SHORT_DELAY MOVLW 0X02
MOVWF LCOUNT
MOVWF HCOUNT
DELAY_LOOP2 DECFSZ LCOUNT,F
GOTO DELAY_LOOP2
MOVLW 0X02
MOVWF LCOUNT
DECFSZ HCOUNT,F
GOTO DELAY_LOOP2
RETURN
;****************************************************************
LCD MACRO DATA1
MOVLW DATA1
MOVWF PORTD
BSF PORTD, 7
CALL DELAY
BCF PORTD, 7
CALL DELAY
ENDM
;****************************************************************
49
LCD2 MOVWF PORTD
BSF PORTD, 7
CALL DELAY
BCF PORTD, 7
CALL DELAY
RETURN
;****************************************************************
MOVLF MACRO DATA2,FILE1
MOVLW DATA2
MOVWF FILE1
ENDM
;****************************************************************
MOVFF MACRO FILE2,FILE3
MOVFFILE2, W
MOVWF FILE3
ENDM
;****************************************************************
SUB1 MACRO VALUE1,FILE4
MOVLW VALUE1
SUBWF FILE4, W
ENDM
;****************************************************************
TABLE ADDWF PCL
RETLW '0'
RETLW '1'
RETLW '2'
RETLW '3'
RETLW '4'
RETLW '5'
50
RETLW '6'
RETLW '7'
RETLW '8'
RETLW '9'
;****************************************************************
STAY MOVLW D'10'
MOVWF COUNTER
LOOP CALL DELAY
DECFSZ COUNTER, F
GOTO LOOP
RETURN
;****************************************************************
DISPLAY MOVFF TEN, STORE
SUB1 0X03, TEN
BTFSC STATUS, 0
GOTO LINE1_A
MOVFF STORE, TEN
SUB1 0X02, TEN
BTFSC STATUS, 0
GOTO LINE1_D
MOVFF STORE, TEN
SUB1 0X01, TEN
BTFSC STATUS, 0
GOTO LINE1_B
GOTO LINE1_C
;*****************************************************************
51
LINE1_A BSF PORTD, 6
LCD 'E'
LCD 'S'
LCD 'T'
LCD ':'
LCD ' '
LCD '2'
LCD '5'
LCD '%'
BCF PORTD, 6
LCD 0XC0
BSF PORTD, 6
LCD 'F'
LCD 'U'
LCD 'E'
LCD 'L'
LCD ' '
LCD 'W'
LCD 'A'
LCD 'R'
LCD 'N'
LCD 'I'
LCD 'N'
LCD 'G'
LCD ' '
LCD '!'
MOVLF B'00000001', PORTE
CALL STAY
GOTO START
52
;*****************************************************************
LINE1_B BSF PORTD, 6
LCD 'E'
LCD 'S'
LCD 'T'
LCD ':'
LCD ' '
LCD '5'
LCD '0'
LCD '%'
BCF PORTD, 6
LCD 0XC0
BSF PORTD, 6
LCD 'B'
LCD 'E'
LCD 'W'
LCD 'A'
LCD 'R'
LCD 'E'
LCD '!'
LCD '!'
LCD ' '
CALL LINE2
MOVLF B'00000010', PORTE
CALL STAY
GOTO START
;*********************************************************************
LINE1_C BSF PORTD, 6
LCD 'E'
53
LCD 'S'
LCD 'T'
LCD ':'
LCD '1'
LCD '0'
LCD '0'
LCD '%'
BCF PORTD, 6
LCD 0XC0
BSF PORTD, 6
LCD 'F'
LCD 'U'
LCD 'E'
LCD 'L'
LCD ' '
LCD 'M'
LCD 'A'
LCD 'X'
LCD 'E'
LCD 'D'
CALL LINE2
MOVLF B'00000100', PORTE ; Red LED "ON"
CALL STAY
GOTO START
;*********************************************************************
LINE1_D BSF PORTD, 6
LCD 'E'
LCD 'S'
LCD 'T'
54
LCD ':'
LCD ' '
LCD '7'
LCD '5'
LCD '%'
BCF PORTD, 6
LCD 0XC0
BSF PORTD, 6
LCD 'F'
LCD 'U'
LCD 'E'
LCD 'L'
LCD ' '
LCD 'A'
LCD 'T'
LCD ' '
LCD 'B'
LCD 'E'
LCD 'S'
LCD 'T'
LCD '.'
LCD '.'
MOVLF B'00000001', PORTE ; Green LED "ON"
CALL STAY
GOTO START
LINE2 ; Display the distance
NEXT MOVFTEN, W
XORWF 0X00, W
BTFSC STATUS, 2 ; TEN=0?
55
GOTO NEXT2 ; Yes, no display tens unit
WORD2 MOVFTEN, W ; No, display tens unit
CALL TABLE
CALL LCD2
NEXT2 MOVFONE, W ; Display ones unit
CALL TABLE
CALL LCD2
LCD '.' ; No, display '.' and decimal point
MOVFDEC_POINT, W
CALL TABLE
CALL LCD2
LCD 'c' ; Display "cm"
LCD 'm'
RETURN
;****************************************************************
MAIN BSF STATUS, RP0 ; Bank 1
CLRF TRISB ; Set PORTB as the output (LCD command)
CLRF TRISD ; Set PORTD as the output (LCD data)
CLRF TRISE ; Set PORTE as the output (LED)
MOVLF B'00000100', TRISC ; Set RC2 as input (Echo of ultrasonic)
; Set RC1 as output (Trigger of ultrasonic)
BCF STATUS, RP0 ; Bank 0
START MOVLF 0X05, CCP1CON ; Set Capture mode in every rising edge
MOVLF 0X11, T1CON ; Enables Timer 1
CLRF PORTC
56
LCD_SETTING BCF PORTD, 6 ; Set RS=0 for LCD receiving command
LCD 0X01 ; LCD command code='00000001' for clear screen
LCD 0X3C ; Set 8 bit interface,2 line mode and 5x10 dot format
LCD 0X0C ; Display ON and no cursor
CLEAR_FILES CLRF DEC_POINT ; Clear all the files
CLRF ONE
CLRF TEN
CLRF HUNDRED
CLRF TIME1
CLRF TIME2
HC_SR04 BSF PORTC, 6 ; Trigger pin is high to emitted sonar pulse
CALL SHORT_DELAY ; at least 10us for emitting sonar pulse
BCF PORTC, 6 ; Stop emitted pulse
AGAIN CLRF TMR1H ; Clear Timer 1
CLRF TMR1L
ECHO_HIGH BTFSSPIR1, CCP1IF ; Is it ECHO raising? (ECHO=1)
GOTO AGAIN ; No, clear Timer 1
BCF PIR1, CCP1IF ; Yes, clear the CCP1 flag
BCF CCP1CON, 0 ; Set Capture mode in every falling edge
ECHO_LOW BTFSSPIR1, CCP1IF ; Is it ECHO falling? (ECHO=0)
57
GOTO ECHO_LOW ; No, increase the content in Timer 1
MOVFF TMR1L, TIME1 ; Store period of ECHO=1 into TIME1
MOVFF TMR1H, TIME2 ; Store period of ECHO=1 into TIME2
BCF PIR1, CCP1IF ; Clear the CCP1 flag
DIVISION1 SUB1 D'58', TIME1 ; Start the division TIME1/58 using subtraction
BTFSSSTATUS, 0 ; Is TIME1 > 58?
GOTO CHECK ; No, check TIME2=0 or not?
MOVWF TIME1 ; Yes, result of (TIME1-58) stored in TIME1
INCF ONE, F ; The times of the operation (TIME-58) will
; stored in temporary file, ONE
GOTO DIVISION1 ; Subtraction again
CHECK MOVLW 0X00
XORWF TIME2, W ; Compare TIME2 and zero
BTFSSSTATUS, 2 ; TIME2=0?
GOTO ADDITIONAL ; No, goto ADDITIONAL because TIME2 has value
GOTO DIVISION2 ; Yes, goto DIVISION2
; to assign result in hundreds, tens and ones unit
ADDITIONAL DECF TIME2, F ; TIME2=1 is same as TIME1=255, TIME2-1 until TIME2=0
MOVLW 0X04 ; 255/58=4.39, so taking 4
ADDWF ONE, F ; Add 4 into the result
MOVLW D'24' ; 4x58=232, 256-232=24
58
ADDWF TIME1, F ; remaining values (23) stored in TIME1
GOTO DIVISION1 ; Subtraction again
DIVISION2 MOVLF D'10', TIMES ; TIMES=10 used for addition of TIME1 10 times (TIME1x10)
MOVFF TIME1, VALUE ; Remaining value in TIME1 stored in VALUE
CHECK2 DECFSZ TIMES, F ; Decrement of 1 in TIMES and then TIME1=0?
GOTO AGAIN1 ; No, subtraction again
GOTO SEPARATION1 ; Yes, separate result
AGAIN1 MOVFVALUE, W ; W=VALUE
ADDWF TIME1, F ; TIME1+VALUE
SUB1 D'58', TIME1 ; TIME1-58
BTFSSSTATUS, 0 ; TIME1 > 58?
GOTO CHECK2 ; Check the TIMES=0 or not?
MOVWF TIME1 ; Result (TIME1-58) store in TIME1
INCF DEC_POINT, F ; Increment of 1 in decimal point *DEC_POINT=1 means 0.1*
GOTO CHECK2
SEPARATION1 SUB1 D'100', ONE ; Start seperate result in hundreds unit (ONE-100)
BTFSSSTATUS, 0 ; ONE > 100?
GOTO SEPARATION2 ; No, for separate result in tens unit
MOVWF ONE ; Yes, result (ONE-100) stored in ONE
59
INCF HUNDRED, F ; Inceament of 1 in hundreds unit *HUNDRED=1 means 100*
GOTO SEPARATION1 ; Separate result in hundreds unit again
SEPARATION2 SUB1 D'10', ONE ; Start separate result in tens unit (ONE-10)
BTFSSSTATUS, 0 ; ONE > 10?
GOTO FINISH_CALC ; No, goto FINIFH_CALC
MOVWF ONE ; Yes, result (ONE-10) stored in ONE
INCF TEN, F ; Increment of 1 in tens unit *TEN=6 means 60*
GOTO SEPARATION2 ; Separate result in tens unit again
FINISH_CALC GOTO DISPLAY ; Display result
END
60