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1. In Fall 2014 students chose the following topics 1 Connect Four in a Digital Approach Connect Four is a two player game which uses a vertical 6x7 grid of 42 LEDs to the game pieces There are red and black pieces one color for each player Game pieces are dropped down one column at a time and the goal is to win by having four of the same color pieces line up either horizontally vertically or diagonally 2 An Armed Alarm System The armed alarm system disables when the correct password is entered If the wrong pass word is entered the alarm sounds and warning lights will flash Otherwise a green LED light will turn on to indicate everything is all right S LSLL 92 e6ed 3 Digital Tachometer and Display The device can detect a rotating speed of an object via an IR sensor The microcontroller counts the number of counts to calculate the RPM of the rotating object 4 Safety Storage System The system is designed to ensure the safety of employees working in walk in cold rooms at 30 C inside a freezer warehouse with the size of a football field The safety storage system can provide a supervisor with an employee s location by means of an LCD display and an LED signal As a result 100 percent of students completed the project in embedded C program In the final exam more conceptual problems in both assembly language and embedded C language were given 100 students successfully passed the course examination 87 5 of th2. Microcontrollers Architecture Programming And Interfacing using C and As sembly Prentice Hall 2008 H W Huang PIC Microcontroller An Introduction to Software and Hardware Interfacing Delmar Cengage Learning 2007 N Salzman P H Meckl Microcontrollers for mechanical engineers from assembly language to controller implementation The 120th ASEE Annual Conference amp Explosion Atlanta Georgia June 23 23 2013 Microchip Technology Inc www microchip com accessed by Jan 2015 Matrix Technology Solutions Ltd E block User Manual www matrixtsl com accessed by Jan 2015 Microchip Technology Inc PICkit 2 Programmer Debugger User s Guide 2008 www microchip com pickit2 accessed by Jan 2015 OL LSLE OZ 9ed Appendix A An Sample of Laboratory Projects Function Call and the Stack This laboratory project familiarizes the students with the function call instruction and the stack References Textbook Chapter 3 2 In this lab we will learn how the stack works while a function call is executed We will run single step and go through two programs using the MPLAB simulator Setup 1 Turn on the personal computer and enter your folder 2 Create a new folder in C drive C CoureName amp Number_yourIntials lab3 in which you store all of your work 3 Create a new project named lab3 and then create a file named as lab31 asm Type the fol lowing program Select the menu item Project gt Build All Relocat
3. the BNZ AGAIN instruction RETURN ZL LGLL 9c Obed 10 Now reset the MALAB SIM by selecting the Debugger Select Tool None menu item Then selecting the Debugger Select Tool MALB SIM menu item again Step into the call function the first call and observe the STATUS register 1 Do all instructions in the subroutine affect the STATUS register Explain 2 If not indicated the instructions that affect the STATUS register What value is stored in the STATUS register when the instructions that affect the STATUS register in the function call are executed Write down the values of the five flags Negative Over ow Zero Digital Carry and Carry after the following instructions are executed and explain the reason a DECF MYREG F with the first loop i e from MYREG 3 to MYREG 2 b DECF MYRKG F with the third loop i e from MYREG 1 to MYREG 0 Part2 Execution of Nested Call Instructions 1 Create a new file and name it as lab32 asm Type the following program to observe the nested call Add the register of TOS Top of Stack to the Watch window to see how the stack pointer moves pkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Lab32 asm A nested function call pkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk list p 18F458 list directive to define processor include lt p18f458 inc gt specific variable definitions COUNT EQU 0x07 M
4. view American Society for Engineering Education 2015 L LGLL 9 e6eY Microcontrollers for Non Electrical Engineering Students Do We Need to Teach Assembly Language Abstract Nowadays most engineering departments offer microcontroller or microprocessors related courses due to the broad applications of computers For Electrical and Computer Engineering ECE or Electrical and Computer Engineering Technology ECET department students nor mally take two or three courses to learn microcontrollers or microprocessors such as assembly language programming embedded system designs computer interfacing and computer organiza tion However for a non ECE program such as Mechanical Engineering Manufacturing Engi neering or Mechatronics Engineering program students most likely only take one Microcontrol lers or Microprocessors course Then teaching non ECE students from the architecture of a microcontroller to broad applications in both low level and high level programming languages can be very challenging In this paper we present a unique approach that has been applied in the Microcontrollers course in the past few years We have limited the content for the exercises in a low level language i e assembly language in 1 understanding how the machine code works 2 comprehending the flow of control for a high level language in a real time system e g the time delay is generated by multiple loops the assembly language is used to
5. 122nd ASEE Annual Conference amp Exposition 2 June 14 17 2015 Seattle WA l g Making Valae for Society Paper ID 12960 Microcontrollers for Non Electrical Engineering Students Do We Need to Teach Assembly Language Dr Shouling He Vaughn College of Aeronautics amp Technology Dr Shouling He is an associate professor of Engineering and Technology at Vaughn College of Aero nautics and Technology where she is teaching the courses in Mechatronics Engineering and Electrical Engineering Technology Her research interests include modeling and simulation microprocessors and PLCs control system designs and Robotics She has published more than 45 journal and conference papers in these research areas Dr Yuhong Zhang Texas Southern University Dr Fangyang Shen New York City College of Technology CUNY Fangyang Shen received his Ph D from Auburn University He had fifteen years research and teach ing experience in wireless networks computer education and high performance computing He had four years experience as a computer engineer He is currently a faculty at New York City College of Tech nology CUNY and published over thirty journal and conference papers He also served as guest editor and associate editor for Journals such as Parallel Computing and Computer and Electrical Engineering and chair for multiple international conferences Dr Shen is an engineering technology and computer education expert with global
6. YREG EQU 0x08 ORG 0x000 MAIN MOVIW 0 MOVWF COUNT CALL DISPLAY GOTO BACK Display subroutine INCF COUNT F MOVFF COUNT PORTB CALL DELAY RETURN Delay subroutine ORG 50H Subroutine started at 50H MOVLW 0x3 MOVWF MYREG NOP No operation but take one instr NOP DECF MYREG F BNZ AGAIN NOP RETURN END Er LSLE e6eg Table A2 Stack Operation for Nested Function Calls Instruction Register PCL The Stack Top of Stack MOVWE COUNT CALL DISPLAY In the subroutine DISPLAY MOVFF COUNT PORTB CALL DELAY In the subroutine DELAY NOP outside of the AGAIN loop RETURN In the subroutine DISPLAY RETURN When you finished your laboratory project successfully 1 Flag down the instructor 2 Show your codes and results 3 Have your instructor grade your lab 4 Keep your program and lab handout for further study VE LGLL 92 abed
7. able You should see a new output window in MPLAB IDE followed by Build Succeeded message pkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkk Lab31 asm The program calls the function DELAY two times to generate time delays pkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk list p 18F458 list directive to define processor include lt p18f458 inc gt specific variable definitions MYREG EQU 0x08 ORG 0x0000 BACK MOVLW 0x55 MOVWF PORTB CALL DELAY MOVLW 0xAA MOVWF PORTB CALL DELAY GOTO BACK This is the delay subroutine ORG 60H Subroutine started at 60H MOVLW 0x3 MOVWF MYREG NOP No operation but take one instruction cycle NOP DECF MYREG F BNZ AGAIN NOP RETURN END Part1 Execution of Call Instructions 1 On the MPLAB IDE menu select Debugger Select Tool MPLAB SIM menu item This specifies that the project will run in simulation mode apart from any microcontroller hardware LL LGLL 9 9ed Select Configure Configuration Bits menu item The pop up window should show that the configuration bits are set in code do not check it and set Oscillator as HS and Watchdog Timer as Disabled Close the Configuration Bits window Select the Ose Trace tab in the Debugger gt Simulator Settings window Set the Proces sor Frequency as 8 MHz Click the OK button Reassemble the file in the project by hitting F10 Select View Program Memor
8. anguage programming using the 8086 microprocessor and embedded systems using PIC16F microcontrol lers For non electrical engineering students we are expected to combine the two courses and provide both fundamental knowledge of microcontrollers and certain experience to apply the mi crocontroller to solve some practical problems in the real world By our analysis we can remove the topics 9 11 in assembly language programing and insert the topics 4 6 after the microcon troller architecture which is the topic 2 in embedded systems The advantage of the new course topic layout is in students learning both microcontroller architecture in assembly language and embedded C for some applications using the microcontroller Thus compromising some topics in microcontroller for embedded systems such as the serial communication in the course 3 Microcontroller course taught for Mechatronics Engineering students The microcontroller course for mechatronics engineering students at Vaughn college is sched uled in the first semester of junior year The students at junior year standing have learned MATLAB programming course and a C programming course After several times of adjust ments including careful examination of the program outcomes and the course objectives PIC18F microcontrollers developed by Microchip Technology Inc are used for the Microcon troller course The course topics are listed in Table 2 Table 2 Course Topics and Lecture Hours De
9. d 2 An engineer in non electrical and computer engineering major may seldom have the oppor tunity to independently develop a software package with time to market and cost efficient constraints for a microcontroller program design Particularly with the rapid development of computer industry the coding efficiency for the memory size and CPU speed may become less important compared to other design factors in manufacturing mechanical or mechatron ics engineering areas 3 It s widely acknowledged that learning assembly language can help understand how a com puter executes a program how a control structure such as for loop and if statement can be converted into machine code how a real time system is designed to satisfy the time con straint and as well as how an interrupted function works From the analysis we can see that complete exclusion of assembly language from a Microcon troller course may not be a good idea As educators in the area of Electrical and Computer Engi neering we know that students need to learn digital electronics so that they gain the knowledge of how a binary or machine code is generated Assembly language is the mnemonic form of the machine code which is used to explain how a computer hardware executes a computer pro gram software Therefore the elimination of assembly language may result in difficulty ex plaining the physical connection between computer hardware and software However limiting the assembly
10. demonstrate how it works 3 the needs for a microcontroller to use hardware architecture such as stack and inter face operations The course schedule is in assembly language programming for about 30 of time and 70 of time is in embedded C programming The course has been taught this way for Mechatronics Engineering students for three years The result is very positive and encouraging The future improvement can consist of 1 making a list for the required knowledge for the course so that students can prepare themselves before they come to the class 2 developing dif ferent levels of problems so that students can practice based on their levels Z SLL 9Z abed 1 Introduction Microcontrollers and microprocessors are playing an important role in a wide range of engineer ing applications Engineers from many disciplines benefit from microcontrollers and micropro cessors in solving engineering problems In most colleges or schools of engineering microcon troller courses are taught by the electrical and computer engineering programs and in some cases by mechanical or mechatronics engineering programs Traditionally the course focuses on teaching assembly language programming since an assembly language is the mnemonic form of the machine code An instructor can systematically discuss the organization of a microcontroller or microprocessor i e ALU CPU data flow registers and memory while students take exer cises in the assembly languag
11. e students got very good grades in solving the problems with the assembly language Mechatronic Engineering is a new program at Vaughn college it received ABET accreditation in Fall 2014 From 2012 to 2014 four groups of Mechatronics Engineering students have complet ed their capstone degree projects All four groups of students have used one or two microcon troller in their projects ranging from PIC18F microcontroller AVR microcontroller Arduino Uno and Arduino Mega as well as other driver boards Due to the solid knowledge background of microcontroller architecture they haven t shown any difficulty in using other microcontroller boards Furthermore due to the acquaintance with embedded C in the PIC microcontroller they were quickly and independently familiarized with the high level language programming envi ronment of other microcontrollers and programs Student evaluation of the course is encouraging Students have learned a lot from the course The knowledge of the assembly language especially in embedded C language helped them to think about more projects for various courses However as we have expected due to the difficul ty of programming languages the common complaint of students is the workload of the course particularly students have to practice both assembly language and embedded C language Most students state that this course is the most intensive course in their semesters One important im provement can be to make a lis
12. e to better understand system architecture of the microcontroller or microprocessor Further in an advanced course such as embedded systems or computer inter facing a high level programming language such as embedded C will be taught with applica tions using microcontrollers However for non electrical and computer engineering students since their primary courses are in their professional areas such as mechanical mechatronics or manufacturing engineering etc the course credits for them to learn microcontrollers embedded systems or even high level programming language are very limited Under the circumstance teaching the microcontrollers or microprocessors for non electrical engineering students has several challenges The first challenge is in the hardship to cover so many types of microprocessors and microcon trollers and various programming languages within a limited amount of time during a semester The second challenging factor is in students possibly having different interests and knowledge backgrounds for microcontrollers or microprocessors while the majority of students have not been exposed to any microcontrollers or microprocessors some students have already pos sessed advanced programming experience from high school Robotics lessons or pure hobbies Both types of students might feel that an assembly language is not quite attractive the former students may not be able to follow the problem solving approach in digital e
13. each what topics should we choose This paper will be organized in the following way in the next section we will analyze the mi crocontroller related courses taught in the Electrical and Computer Engineering program at a col lege where one of the authors was teaching Further we will discuss how an assembly language may help students understand microcontrollers and what topics we should teach using assembly language The third and fourth sections present the course layout taught at Vaughn college and the evaluated results Conclusion will be given in the fifth section 2 Analysis on teaching a microcontroller course with or without an assembly language In terms of teaching an introductory microcontroller course without assembly language the Electrical Engineering Technology EET program at Purdue University has successfully taught students using embedded c However as far as our knowledge is concerned there hasn t been found evidence of a university teaching purely embedded C in an introductory microcontroller course in an ECE program Furthermore several microcontroller textbooks ane popularly used in U S universities have covered both the assembly language and embedded C in almost all samples which really provides the flexibility for an instructor to choose what to teach On the other hand due to the fact that too much information needs to be covered in an introductory mi crocontroller course choosing proper topics to teach become
14. language study only for students to understand how a computer works we can save a lot of time to enhance students programming skills in a high level language such as embedded C From the point view of an educator we consider the major difference between the assembly language of a microcontroller and the embedded C language is that the former can be used to ex plain the working principle of a computer more easily and the latter can be exploited to solve en gineering problems more efficiently Table1 Course Topics for Assembly Language Programming and Embedded Systems Assembly Language Programming Embedded Systems ee PSOE eS Introduction to Embedded Microcontroller 2 8086 Family Hardware Specification PIC16F Microcontroller Architecture 3 Memory and Bus Architectures Introduction to Embedded C Programming 4 Assembly Language Fundamentals Arrays Pointers and Function Calls 5 Real Mode Addressing Port Operations and Interrupts 6 Stack and Procedures Timers and Timer 0 Programming 7 Interrupts DOS Function Call and BIOS Timer and Capture Compare Module 8 Conditional Jumps and Loops Timer 2 and PWM Module 9 High Level Logic Structures Serial I O SPI and I2C 10 Arithmeticl Multiplication and Division UART USART Communications 11 Arithmetic2 Shift Rotate Instructions GISLL9 e6eY Table 1 shows the course layouts to teach students in the ECE department assembly l
15. lectronics and mi croprocessors so quickly and the latter students couldn t see the direct help to solve some ad vanced problems such as programming smart phone or tablet applications Especially from the professional development point of view when non ECE engineering students come to a Micro controller course they are anticipated to effectively solve problems in their professional areas rather than a deep understanding of the structure inside a microcontroller or a microprocessor Therefore as educators we have to ask the problem is the traditional approach to teach the Mi crocontrollers or Microprocessors course adequate for non ECE engineering students From a practical perspective assembly languages are seldom used to solve problems in the real world since it is very easy to make bugs and quite difficult to find and debug them Most indus trial employers may prefer engineering graduates to master at least one high level programming language for microcontroller applications Hence the further question is do we need to teach the assembly language of a microcontroller in the microcontroller course for non electrical engi neering students To answer it we consider the following questions may assist us in approach ing a logical conclusion 1 How does learning assembly language programming help students understand a microcon troller or microprocessor CLS OZ obed 2 If we need to choose some parts of an assembly language to t
16. ng and development LIGLL92 96ed Figure 2 EB006 V9 PICmicro microcontroller programmer board and PIC Kits2 programmer As shown in Table 2 and Table 3 we only used first four weeks i e one third laboratory times to do the exercises for the PIC assembly language The topics covered 1 machine code formats with the opcode and operand 2 status register for jump instructions 3 implementing time de lay using jump instructions and calculating exact time delay in assembly instructions 4 exam ining the hardware stack through the implementation of function calls After the first four weeks we start to review C or MATLAB program for the flow of control in a high level language and introduce the port operations for PIC18F microcontrollers Students began to program in embedded C with bitwise operations and flow of control In lab 5 students are taught to wire an LCD module and display some text information on the module Then ADC conversion and timer operations are introduced in lab 6 and lab 7 Lab 8 is devoted to interrupt programming Since students already know the stack operation interrupt concepts are relatively easier for students to accept Finally the laboratory exercises end by examining control of DC motors using PWM signal and the basic concepts about capture and compare modes 4 Result and Evaluation For the class a final project was assigned Students individually choose the topics and complete them in groups
17. s very important To teach an assembly language in a Microcontroller or Microprocessor course people working in the area of embedded systems may provide the following reasoning 1 Assembly language is the mnemonic form of machine language For some hardware features for example port access an assembly language is the most efficient way to program a micro controller or a microprocessor 2 A simple rule of thumb 90 of the time is spent executing 10 of the code has been gen erally known by computer engineers Therefore to complete a task with fully making use of a processor i e push it to the limits in terms of coding efficiency cost performance and power consumption an assembly language is still the best choice 3 Learning assembly language can help students understand more about microcontroller struc ture Particularly for instruction formats the flow of control structure the hardware stack operations as well as the interrupts an assembly language has to be used to show the archi tecture of a microcontroller or a microprocessor and do exercises For above arguments we can analyze as follows 1 Most modern embedded C compilers have already adopted bit wise operations and memory mapped IO Therefore in terms of port or pin access majority embedded C language com pilers for a microcontroller or microprocessor have similar functions as the corresponding assembler in its assembly language VISLL 9 abe
18. so shown in Figure 2 Table 3 Laboratory Projects Lab No Hours Topics Oo Introduction to MPLAB IDE simple assembly program Status register and time delay examination in assembly language Function calls and the stack operation Microcontroller hardware board and embedded C programming LCD module Interfacing with PIC Microcontroller ADC Conversion and analog signal display Timer0 and digital clock Interrupts and Timer0 Timer overflow interrupt Ol aOl AILND Nn AIIN eR DNL DI NDI DI DAD WD W Ww PWM module and DC motor control IRS lob MPLAB IDE vaD Program Memon Bie Edt View Project Debugger Programmer Jools Configure Window Help os Da sA t Checksum 0x7be5 Debug aeu GBeOd Sa pno PeEO rere Program Memory Update Binary MPLAB SIM PICREF4S80 pd wo nowzdee 20MH bank0 Figure 1 MPLAB IDE EB006 V9 PICmicro board is a low cost and flexible microcontroller programmer This board can be used with conventional microcontroller programs that generate hex code for the PIC fami ly MPLAB C compilers etc The board provides clean access to all input output lines on the relevant PICmicro microcontroller device These are presented on 9 pin D type connectors 8 bits and earth A range of additional E blocks boards can be plugged into these D type connect ors to provide a rapid prototyping system for learni
19. t for the required knowledge for the course which allows students to prepare for the class in advance The second improvement is to develop different levels of problems so that students can practice based on their levels 5 Conclusion In this paper we have discussed teaching a Microcontrollers course for non electrical engineer ing students The proposed coverage is based on the limited credits available and practical expec tation for the students in non electrical engineering majors Our goal is to make the microcon troller more practical without loss of essential knowledge necessary for students to learn from the microcontroller course i e making the microcontroller as a design tool to solve engineering problems rather than spending considerable amount of time to learn assembly language pro gramming skills 6 LSLL 9 obed Bibliography A F Mondragon and A Becker Gomez So many educational microcontroller platforms so little time The 119th ASEE Annual Conference amp Explosion San Antonio Texas June 10 13 2012 S He Laboratory design for introductory course of microprocessors 2013 IEEE Frontiers in Education Conference FIE 2003 R H Barnett S Cox amp L D O Cull Embedded C Programming and the Atmel AVR Delmar Learning Clif ton Park NY 2003 M Mazidi R McKinlay amp D Causey PIC Microcontroller and Embedded Systems using Assembly and C for PIC18 Prentice Hall 2007 B B Brey Applying PIC18
20. voted to Each Topic Week Hours Topics 1 2 Microprocessor architecture and PIC18 microcontroller 2 2 PIC18 assembly language directives instruction formats 3 2 Branch looping and time delay 4 2 The stack and function calls 5 6 4 Introduction to embedded C programming data type and arithmetic op erators and bitwise operators flow of control 7 2 Function calls and arrays in embedded C with interfacing a liquid crystal display LCD module 8 2 PIC18 features and analog to digital A D conversions 9 Course Review Midterm Exam 10 12 6 Timer programming and interrupt programming 13 14 4 Capture compare PWM programming 15 Course Review Final Exam Table 3 shows the laboratory projects in the laboratory exercise sections where the content of laboratory project 3 is included in Appendix A For the laboratory exercises MPLAB Integrat ed Development Environment IDE as shown in Figure 1 is used to program the source code in PIC assembly language and embedded C language MPASM assembler and PIC C18 Compiler are used to convert the source code into the corresponding machine code For the implementa 9 LSL OZ abed tion the EB006 V9 PICmicro microcontroller programmer board developed by Matrix Technol ogy Solutions Ltd has been used to test and demonstrate the program Figure 2 PIC Kit2 in circuit programmer is used to download the code into PIC18F microcontrollers which is al
21. y menu item Find the location of the main program and the called program subroutine Explain the reason why the subroutine is placed at the address 0x0050 Select the menu item View gt Hardware Stack which shows the stack and return address window Select the menu item View Watch This shows the values of selected SFRs and defined variables GPRs or Symbols Now highlight the SFR WREG and add it to the window Similarly add the registers PORTB PCL and Status Close the Project window and Output window by clicking the close sign on the up right corner of each window Select the Window Tile Horizontally menu item so that you can see 1 the source code 2 watched registers 3 hardware stack 4 program memory Move your mouse in the source program and click it to activate the window and press F7 to step through the program instruction by instruction In the File Register window and Watch window notice the register at the Program Counter Low PCL register at OxFF9 and the Stack Fill the following table for the contents of the five registers after each in struction is executed Table Al Stack Operation for Function Calls Instruction Register PCL The Stack TOS MOVWE PORTB Before the first call CALL DELAY In the called program NOP After the BNZ AGAIN instruction RETURN In the main program MOVWE PORTB Before the second call CALL DELAY In the called program NOP After
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