MILES: A Microcontroller Learning System combining Hardware and Software tools

Transcription

1 MILES: A Micrcntrller Learning System cmbining Hardware and Sftware tls Luis F. Ferreira, Emili L. Mats, Luis M. Menendez and Enrique Mandad Institute fr Applied Electrnics, University f Vig (Spain) lferreira@uvig.es Sessin F4E Abstract - Micrcntrllers are ne f the mst imprtant devices implementing cmmunicatin and electrnic cntrl systems. By this reasn micrcntrller applicatins learning is essential nt nly fr electrical engineers but als fr mechanical, chemical, industrial, etc. But these engineers need a different way f learning, cmbining theretical and practical appraches. This paper presents MILES (Micrcntrller Learning System), which is a multifunctinal mdule fr micrcntrller based system design and applicatins learning. MILES cmbines a hypermedia sftware tl running n a persnal cmputer with a hardware develpment bard based n a flash PIC micrcntrller. Flash micrcntrllers make easier reprgramming and testing applicatins n the fly, ffering the pssibility f functinality change. MILES cnstitutes an innvative way f learning in the sense that invlves a hardware tl with an user-friendly hypermedia tutrial and can be used by electrical engineers as well as by ther engineers. T achieve this feature it is able t run nt nly as a develpment system f micrcntrller applicatins but as a demnstratin system by means f electrnic mdules with a practical functinality (fr instance, ptelectrnic cunting systems, stepping mtr cntrl, RF cmmunicatins circuits, etc). Index Terms - Cmputer aided learning, Cnceptual maps, Develpment bard, Hypermedia, Micrcntrllers, PIC. INTRODUCTION Micrcntrllers are integrated cmputers used in many different cntrl and cmmunicatins applicatins. Due t that, learning micrcntrller applicatins is necessary nt nly fr electrical engineers but als fr mechanical, chemical, industrial nes, etc. But because micrcntrllers are integrated cmputers, they cnstitute a cmplex technlgy including many interrelated cncepts. By this reasn micrcntrller educatin is nrmally based n particular devices. But, althugh this apprach gives t the student a practical educatin it des nt give the glbal visin which is necessary t be able t specify and design micrcntrller based systems. This paper presents MILES (Micrcntrller Learning System) which is a system cmbining a hypermedia tl running n a persnal cmputer with a multifunctinal hardware mdule develpment bard, a sftware develpment tl and a prgramming tl (Figure 1). S MILES can be divided in tw subsystems: A hypermedia subsystem. An applicatin develpment subsystem cmbining a hardware bard and sftware CAD tls. Hypermedia system Prgramming tl FIGURE 1 BLOCK DIAGRAM OF MILES HYPERMEDIA SYSTEM Develpment bard Develpment tl Due t the fact that micrcntrllers cnstitute a cmplex technlgy [1], the hypermedia system has been dne using the methd t btain the descriptive mdel f a cmplex technlgy develped by the Institute fr Applied Electrnics f the University f Vig [2]. This methd is represented in Figure 2 and cmprises fur principal stages: Firstly, many different representative systems r devices are chsen. In the secnd stage the selected systems are analyzed in detail t define the cncepts assciated t the technlgy. This task is carried ut in tw different phases: All the cmmn characteristics are determined and classified t define the general characteristics r basic cncepts f the cmplex technlgy. In the secnd phase the basic cncepts are characterized (including functinality, implementatin, architecture, etc.) taking int accunt the specific characteristics f each particular system in such a way that the subcncepts f the descriptive mdel are btained as well as its dependence relatins. The same subcncept can be present in /05/$ IEEE Octber 19 22, 2005, Indianaplis, IN F4E-7

2 different systems but the set f subcncepts assciated t each system can be different. In the third stage all the basic cncepts and subcncepts are structured t btain the descriptive mdel. Finally, the descriptive mdel must be tested t verify its ability t describe nt nly the systems chsen t btain the mdel but, all the cmmercial systems knwn. Develping descriptive mdels is a tedius task requiring a lt f time and effrt. Nevertheless, nce the final result is btained we achieve a very useful tl fr the analysis f cmplex technlgies as well as the particular systems included in them. Besides, if new systems are develped, updating the mdel with the inclusin f new characteristics is Sessin F4E The elements being used t implement the systems. The different elements can als be described by means f cnceptual maps. The cncepts that characterize the different types f systems. Figure 4 shws the micrcntrller cnceptual map. Micrcntrllers are integrated cmputers cmpsed f a memry unit, an arithmetic and lgic unit and a cntrl unit. These three cmpnents are cmbined by means f the mst imprtant cncepts f the micrcntrller technlgy: internal architecture, external architecture and I/O interfaces. SELECTING A REPRESENTATIVE SET OF REAL SYSTEMS FIRST STAGE DEFINING THE FUNDAMENTAL COMMON CHARACTERISTICS BASIC CONCEPTS SECOND STAGE DEFINING THE PARTICULAR CHARACTERISTICS: - Functinality - Implementatin - Architecture - Technlgy SUBCONCEPTS CONCEPTS DEFINE very easy. ESTRUCTURING THE INFORMATION TO DEVELOP THE DESCRIPTIVE MODEL VERIFICATION FIGURE 2 COMPLEX TECHNOLOGIES CHARACTERIZING METHODOLOGY Once the descriptive mdel is btained, it is necessary t use a graphical representatin f it. S we studied the applicatin f cnceptual maps being used at present nly t describe general human knwledge areas [3] [4] [5] [6]. Figure 3 shws the cnceptual map f a cmplex technlgy divided int tw main parts: FIGURE 3 CONCEPTUAL MAP OF A COMPLEX TECHNOLOGY FIGURE 4 MICROCONTROLLER CONCEPTUAL MAP Due t the interrelatin f the cncepts it is interesting t describe the micrcntrller map using hypermedia with the map cncepts as key wrds t achieve a nn sequential access t the infrmatin. Every cncept is explained using html pages cmbined with a brwser and related t the sftware tls t implement the hypermedia system. The cncepts are rganized in lessns and described using text, pictures, diagrams and vides. Figure 5 is an example f a html page f the hypermedia system. The user can als navigate thrugh the lessns using a friendly interface [7] [8]. T simplify navigatin, every lessn has linkages with a glssary, including definitin f the different cncepts using multimedia resurces. The hypermedia system is divided int the fllwing lessns: Micrcntrller fundamentals PIC family f micrcntrllers descriptin Hardware and sftware CAD tls fr micrcntrllers MILES electrnic develpment bard descriptin Prgramming micrcntrllers applicatins Prpsed exercises Autassessment The interface includes a buttn t execute experiments. This buttn is active in thse pages cmbining thery with the develpment bard described next. The system allws the user /05/$ IEEE Octber 19 22, 2005, Indianaplis, IN F4E-8

3 Sessin F4E t select amng many predefined exercises. When the buttn is pressed the cde is transferred t the PIC prgram memry using the prgramming tl and the micrcntrller autmatically runs the prgram withut any user interventin. Amng the experiments develped and ready t be executed frm the tutrial are: Basic arithmetic peratins Cnversins between numeric cdes Using utput peripheral elements Using input peripheral elements Time cntrl with PIC Anther PIC resurces experiments Applicatins FIGURE 6 ELECTRONIC DEVELOPMENT BOARD FIGURE 5 HYPERMEDIA SYSTEM HTML PAGE The mst relevant characteristics f the develpment bard are: Cntains peripheral devices fr simple digital system implementatin and verificatin. It is expandable t cnnect external peripheral elements fr cmplex digital system implementatin. Cnstitutes a rapid prttyping develpment system because all the micrcntrller pins are available fr peripheral devices. Can be used as an In circuit debugger cnnecting the micrcntrller t a prttype bard. It is a self-learning riented system due t its switching n the fly capability frm prgramming t running peratin mde. DEVELOPMENT SYSTEM The develpment system included in MILES is based n PIC micrcntrllers frm Micrchip Technlgy Inc. [9] [10] and cnsists f: An electrnic develpment bard (Figure 6). CAD sftware tls running in the persnal cmputer t: Edit the surce cde. Cmpile the prgram. Simulate the applicatin perfrmance. Prgram the micrcntrller instructin memry. I. Develpment bard Figure 6 shws a picture f the develpment bard and Figure 7 represents its blck diagram including a pwer supply, three sckets fr PIC micrcntrllers f 18, 28 and 40 pins, a DB25 cnnectr t the persnal cmputer parallel prt, tw expansin cnnectrs and a DB9 cnnectr t interface with a RS-232 serial prt. The bard als includes a set f I/O peripheral elements: eight LEDs, three seven segment displays, eight micrswitches, a pulse generatr switch and a ptentimeter t generate a variable analgue signal. FIGURE 7 BLOCK DIAGRAM OF THE MILES DEVELOPMENT BOARD II. CAD sftware The CAD sftware is made up f tw tls. One f them is MPLAB prvided by Micrchip t edit, cmpile and simulate the prgram. The secnd ne is a freeware flash memry prgramming tl available in Internet. PROGPIC [12] r ICPROG [13] can be used (Figure 8) /05/$ IEEE Octber 19 22, 2005, Indianaplis, IN 35th ASEE/IEEE Frntiers in Educatin Cnference F4E-9

4 Sessin F4E MILES can als be used in cntinuus and self-learning educatin due t the lw cst f the develpment bard and the free available develpment sftware. MILES EXPERIENCES FIGURE 8 ICPROG PROGRAMMING TOOL INTERFACE USING MILES MILES can be used by engineers f any speciality t learn the mst imprtant applicatins f micrcntrllers as well as by electrical engineers t becme experts in micrcntrllerbased system design. T achieve the first perfrmance the hypermedia subsystem cntains a set f predesigned prgrams selected t shw the mst imprtant micrcntrller applicatins. The explanatin f every prgram is cmbined with a vide f the develpment bard where the results f the prgram executin are shwn (Figure 9). T achieve the secnd perfrmance the hypermedia subsystem is linked with the CAD tls t facilitate the prgram develpment and executin using the develpment bard. The system has been tested with sixty pregraduate mechanical engineers with a basic knwledge f digital systems and electrnic devices fundamentals n a subject n micrcntrller fundamentals and applicatins. Tw grups were dne, grup A and grup B, each ne with thirty students. Students f grup A went t a micrcntrller theretical master class being implemented during several years and did nt use MILES. Students f the grup B went t a classrm where the prfessr explained the thery and prpsed exercises that the students verified in the MILES develpment bard. The grup B students culd als use the hypermedia system t clarify the main cncepts and verify their level f knwledge. At the end f the classes, a pll has been taken t verify the satisfactin f the students. 38 % f the grup B students cnsidered the subject very interesting (8 % in grup A), 50 % cnsidered the subject interesting (36 % in grup A), and 6 % cnsidered it bring r useless (58 % in grup A). The final examinatin results were als mtivating: a 15 % mre rate f passing students in grup B. Many students expressed the view that the hypermedia system needed a friendly guide t the instructins f the different PIC micrcntrller. This facility has been included in the latest versin f the hypermedia tl. At present MILES is being used n cntinuus educatin curses fr mechanical and electrical engineers with very gd results. Educatrs find MILES very useful because it is nt a clsed system: they develp and add their wn exercises prgrams and use the develpment bard expandability t adequate the system t the level f their curses. CONCLUSIONS FIGURE 9 EXAMPLE OF A PROGRAM DESCRIPTION USING A VIDEO The system can be used by the prfessr in the classrm cmbining tutrial and practical experiences. It can substitute the master class if the prfessr prpses small cntrl systems design t be verified with the develpment bard. MILES is a micrcntrller learning system prviding theretical knwledge cmbined with practical ne. It can be used t learn micrcntrller based systems design as well as t demnstrate their industrial applicatins. T achieve this perfrmance, it includes a develpment bard with an analgue multiplexer and a DC t DC cnverter prviding the bard with autmatic switching capability frm prgramming t running peratin mde. MILES is apprpriate t achieve asynchrnus distance learning due t the lw cst f the develpment bard cmpnents and the free available develpment sftware. MILES is being used with a great success in cntinuus educatin curses. NOTE: MPLAB is a trademark f Micrchip Crp. ACKNOWLEDGMENT This wrk has been funded by Xunta de Galicia (Spain) under prject PGDIT02SIN34001CT /05/$ IEEE Octber 19 22, 2005, Indianaplis, IN F4E-10

5 REFERENCES [1] Brckman J.M., "Cmplex Systems and Emergent Technlgies", Reprt f the Center fr Integrated Design Seminar, June 29, [2] Valdés M.D., Mure M.J., Mandad E., Hypermedia: a tl fr teaching Cmplex Technlgies, IEEE Transactins n Educatin, N. 4, Nv. 99. [3] Nvak Jseph D., Cncept maps and Vee diagramas: tw metacgnitivies tls fr science and, mathematics educatin, Instructinal Science, N. 19, 1990, pp [4] Nvak Jseph D., Clarify with cncept maps, The Science Teacher, N. 58(7), 1991, pp [5] Nvak Jseph D., Gwin D.B., Learning t learn. Cambridge University Press, Massachusetts, USA, [6] Ontría A. et al., Mapas cnceptuales. Una técnica para aprender, Narcea S.A. Ed., Madrid, Sessin F4E [7] Alessi S.M., Trllip S.R., Multimedia fr learning, Alling and Bacn, Massachusetts, 3 a ed., [8] Gnzález J., Pérez M. et al., MAJA: A methdlgy t develp multimedia/hypermedia sftware fr educatin, Prceedings f ED- Media 99, Seatle, Jun. 99. [9] Predk M., Prgramming and custmizing PICmicr micrcntrllers, Secnd Editin, Ed. McGraw Hill, [10] Micrchip Crp. Hme Page. [11] Mandad E. et al., Dispsitivs lógics prgramables y sus aplicacines, Ed. Thmsn-Learning, [12] Freeware Sftware PROGPIC, [13] Freeware Sftware ICPROG, /05/$ IEEE Octber 19 22, 2005, Indianaplis, IN F4E-11