2 Table of Contents CHAPTER 1 ... 3 INTRODUCTION ... 3 1.1 PROJECT BACKGROUD ... 3 1.2 PROBLEM STATEMENT ... 5 1.3 OBJECTIVES ... 6 1.4 SCOPE ... 7 CHAPTER 2 ... 8 LITERATURE REVIEW ... 8
2.1 WHY USE PIC16F877A ... 8
2.2 WHY USE ULTRASONIC SENSOR HC - SR04. ... 9
2.3 WHY USE LCD-DS-LCD-162A. ... 10
CHAPTER 3 ... 11
METHODOLOGY ... 11
3.1 WORK PROGRESS FLOW ... 11
3.2 METHODS (PROGRAM USED) ... 12
3.3 HARDWARE DEVELOPMENT... 17
3.4 SOFTWARE DEVELOPMENT ... 22
CHAPTER 4 ... 30
RESULT AND ANALYSIS: ... 30
CHAPTER 5 ... 35
COST EVALUATION……….35
5.1 BILLS OF MATERIALS AND COMPONENTS……….35
5.2 OVERALL PROTOTYPE PRICE……….36
CHAPTER 6……….37
CONCLUSION ... 38
6.1 RECOMMENDATION ... 39
REFERENCES ... 41
3
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.
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.
4 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.
5
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.
6
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.
7
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.
8
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.
9
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.
10
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.
11
CHAPTER 3
METHODOLOGY
3.1 WORK PROGRESS FLOW
PLANNING
Making researches on topics that will be proposed. 5V DC power supply schematic circuit will be obtained from any available sources such as internets or books.
DESIGN
Topics proposed among team members. Best topic for group project will be confirm to avoid same topic with the other groups. Size, cost, materials used are considered during this process.
BUDGET
List of all components and material that will be used. The total cost of proposed project calculated. Method of obtaining materials that will be used are discussed during this process.
PROPOSAL
Previous researches and information will be compiled into project proposal.
PROJECT PROGRESSION
Circuit will be designed using selected software and fabricated on PCB. Related electronic components will be soldered throughout this process.
FINDINGS
Circuit will be simulated. Circuit also will be tested and any related data and outcomes will be collected for future references and revisions.
ANALYSING AND PROJECT TESTING
The project‟s simulation results will be analyzed. The results will be compared. Any error or failure in this project will be overcame. Last touch for project‟s prototype will be made. Project will be tested and verified
during this phase.
FINAL REPORT AND PRESENTATION
12
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 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.
18 Figure 8 : Power source circuit board
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
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
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.
START
Gap between ultrasonic sensor with object infront
of it
Ultrasonic sensor detect the distance of the gap
Distance measurement in percentages send to PIC16F877A
PIC16F877A send data to output display
Display “FUEL USED: “ on LCD
Display the distance measurement in percentages on
LCD
END
23
LCD INTERFACE:
Figure 13: Flow chart of the assembly code for the LCD interface (main)
24 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)
26 Figure 17 : Flow chart of the assembly code for the LCD interface (M2 subroutine)
27 Figure 19 : Flow chart of the assembly code for the LCD interface (continue)
28
ULTRASONIC SENSOR INTERFACE:
BEGIN
Select bank 1
Set all pin at PORT A as output
Clear PORT B and PORT D.
Set pin RC2 as input
Set as digital pins using ADCON1 register (bit 0110) Enable CCP1 Insert interrupt Clear pin RC6 Set pin RC6 Clear pin RC6 DELAY SDELAY
Clear TMR1H and TMR1L register
Test bit=1 for PIR1 and CCP1IF
Clear PIR1, CCPI1F and CCP1CON register
YES
NO
Test bit=1 for PIR1 and CCP1IF
YES NO
Clear PIR1, CCPI1F and CCP1CON register
DISPLAY
END
29 DISPLAY LINE1 LINE2 END LINE1 Enable PORT D Display “RANGE :” END LINE2 Clear PORT D Enable PORT D Display distance value Display “ cm” Data from ultrasonic sensor END
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.
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.
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
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 2.00
2. Ceramic Capacitor 100 µF 2 0.65 1.30
3. Ceramic Capacitor 0.01 µF 2 0.15 0.30
4. Resistor 220 Ω 1 0.05 0.05
5. 1N4007 1 0.20 0.20
6. Light Emitting Diode (LED) 1 0.40 0.40
7. 2 Pin Terminal Block 2 1.20 2.40
8. DC Jack 1 2.00 2.00
9. DC Power Adapter (Variable) 1 18.00 18.00
10. 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 18.00 2. Potentiometer 5k Ω 1 1.20 1.20 3. PIC16F877A 1 17.00 17.00 4. Jumpers 1 12.00 12.00 5. 4 MHz Crystal Oscillator 1 2.00 2.00 6. 22 pF Ceramic Capacitor 2 0.15 0.30 7. 40-Pin IC Socket 1 0.70 0.70
8. Straight 2mm Female Header 1x40 Ways 2 1.20 2.40
9. HC-SR04 Ultrasonic Sensor 1 39.00 39.00
10. Printed Circuit Board 1 * *
Overall Price (RM) 92.60
*Components/materials are obtained from laboratory
37
Prototype
No. Items Quantity Price of Each Unit (RM) Total Price (RM)
1. Plastic Board 1 4.00 4.00
2. Polystyrene Blocks 1 * *
3. Water Flask 1 4.00 4.00
4. 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:
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 within the tightest of space envelopes and withstand the harshest of environments.
40 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' MOVWF PORTD
43 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 MOVLW 'M'
44 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 ; MOVWF PORTD
45 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: MOVLW 0xFF
46 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
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 ;**************************************************************** LCD2 MOVWF PORTD
49 BSF PORTD, 7 CALL DELAY BCF PORTD, 7 CALL DELAY RETURN ;****************************************************************
MOVLF MACRO DATA2,FILE1
MOVLW DATA2
MOVWF FILE1
ENDM
;****************************************************************
MOVFF MACRO FILE2,FILE3
MOVF FILE2, 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' RETLW '6'
50 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 ;***************************************************************** LINE1_A BSF PORTD, 6
51 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' LCD 'S'
53 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' LCD ':'
54 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 MOVF TEN, W
XORWF 0X00, W
BTFSC STATUS, 2 ; TEN=0?
GOTO NEXT2 ; Yes, no display
55
WORD2 MOVF TEN, W ; No, display tens unit
CALL TABLE CALL LCD2
NEXT2 MOVF ONE, W ; Display ones unit
CALL TABLE CALL LCD2
LCD '.' ; No, display '.'
and decimal point
MOVF DEC_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
LCD_SETTING BCF PORTD, 6 ; Set RS=0 for LCD
56
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 BTFSS PIR1, 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 BTFSS PIR1, CCP1IF ; Is it ECHO falling? (ECHO=0)
GOTO ECHO_LOW ; No, increase the content in Timer 1
57
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
BTFSS STATUS, 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
BTFSS STATUS, 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
ADDWF TIME1, F ; remaining values (23)
58
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 MOVF VALUE, W ; W=VALUE
ADDWF TIME1, F ; TIME1+VALUE
SUB1 D'58', TIME1 ; TIME1-58
BTFSS STATUS, 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)
BTFSS STATUS, 0 ; ONE > 100?
GOTO SEPARATION2 ; No, for separate result in
tens unit
MOVWF ONE ; Yes, result
(ONE-100) stored in ONE
INCF HUNDRED, F ; Inceament of 1 in hundreds unit *HUNDRED=1 means 100*
59
GOTO SEPARATION1 ; Separate result in
hundreds unit again
SEPARATION2 SUB1 D'10', ONE ; Start separate result in tens unit (ONE-10)
BTFSS STATUS, 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
