Lab1: Basic Stamp II Digital I/O 305
Contents
1. Lab1 Basic Stamp II Digital I O 305 554A Microprocessors for Mechanical Systems 6 October 1999 Group D Yeow Wei Pang Anny Xie Abstract This report covers an introductory laboratory exercise done to interface Basic Stamp II digital I O to various devices an LED a seven segment display TIL306 a 4x4 matrix keypad and a serial LCD display The exercises involved include flashing an LED displaying numeric inputs on the TIL306 and implementing a digital stopwatch on the LCD Program codes used to implement the above are provided with comments so that readers can easily see how we did it A components price list is also provided for those who want to reproduce what we have done 1 Introduction One of the objectives of the laboratory exercise is for us to get acquainted with the PBASIC programming language This is easily done because the PBASIC instruction set is relatively short and each command is well documented in the Basic Stamp Il manual Having previous programming experience helps but when we cannot get the program to work the way we want the best place to go to is always the manual Another objective is to interface the matrix keypad This involves both hardware and software implementations The hardware part is to connect the leads to the correct pins and setting up resistors to prevent the stamp from frying The software part is to get the program to scan the pins for inputs this will be elaborated later After2. Cl checked heh the whectec Lead on Cit LEG dice JE Ta OMIE 1 ii amupkia Tishu of tha LEG LE FE E when Betcone is prams LID x mE ahh E at Plashhe 2nce peer PESE En oll oo ff iie a ll Bi bhiin Beco Lae Pretitti LAD HC opE o a d a a flaring ak id ag Ce Gi futtce 0 ahoaldd be preeeaed for cme gehicird I hibri CREC Tiki pidid Figere kl ssepletep gee lesp te afF the LET r i Interfacing a Seven Segment display LI gL Eo Tie TIZ JL ee re li bihi ig Gani J tee mangn npr giepley miL dALeplap the Jeet numari key peered an the BRtria bey paed 7 a a m db hb bh C T s ah lle p k d _ m g lki jij jie jdi Figen Teplesent a digital stepwateh on the LOD Lrtarfeare a LOF ALeplay eelenm pral marrara 2 han Pottors is premeed LED flamkee s per Bed od Sone leah diapla kni upite the Line 1s i mim a Ube Bet d eke PUCK iE Poe DED KLJ Bn Goo Erri Liat e lipiid Lae ad Die ple fi ile LES a han Dottor is prarrad epeaim the setch rerete titel before begdoniog the count again Lak H a ja Cit doce L E 7 bo _ oe pial Pas a ILE a i Figures J 7 2 Hardware Used 2 1 Basic Stamp Il and Board of Education The BASIC Stamp II is a postage stamp sized product of Parallax Company A BASIC Stamp is a PIC microcontroller that has been customized to understand the BASIC programming language The use of the BASIC lan
3. The other team member checks all the connections before powering up the system 3 In the Basic Stamp programming window edit and run the program Make sure the PC is connected to the Board of Education via the serial cable 4 Press button 1 on the keypad check the LED 5 If LED is not flashing correctly plug out the power first Repeat steps 2 5 until the LED does the right thing Then press button 4 Check the result and edit the program if needed 6 Measure and tune the accuracy of the system by comparing it with a watch clock 3 1 4 Documented Source Code rrrrrrrrrrrrrrrrrrrrrrrprrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrirrit Grou Lab Desc T T T T T T T T T T T T T T T T T TETU target flag flag target DIRS LOOP1 LOOP2 LED_ON LED_OF p D Pang Yeow Wei Xie Ling 1 Basic Stamp II Digital I O ription Program is used to interface a matrix keypad to an LED Flashing of the LED is We could have used only 2 pins 1 input controlled by 2 buttons implement this However the lab rrrrrrrrirrrrrrrrrrrrrrrprprrrrrrrrrrrrrrrrrrrrrrrrri rd var byte var bit 0 0 1000000011110000 LOW 5 HIGH 4 BUTTON 071 255 0 target t LED ON GOTO LOOP2 LOW 4 HIGH 5 BUTTON 0 1 255 0 target 1 LED_OFF IF flag 1 THEN LED_ON GOTO LOOP1 flag 1 HIGH 15 pause 50 LOW 15 pause 950 GOTO LOOP2 F flag 0 GOTO LOOP1 305 554A Micropr
4. the program Make sure the PC is connected to the Board of Education via the serial cable 4 Check the TIL 306 display It should show 0 and a blinking decimal point 5 If TIL306 display is not correct plug out the voltage source Repeat steps 2 5 until it has the right display Then press any numerical button on the keypad Check the result It should display the last button pressed Edit the program if needed 3 2 3 Documented Source Code Deleted 3 3 Lab Exercise 3 Implement a Digital Stopwatch On The LCD 3 3 1 LCD Preliminary Tests Check the DB9 pin I O table of the LCD manual Check the DB9 pin I O table of the Basic Stamp II manual Use a multi meter an ohmmeter in this case to verify which side of the serial line should go to the LCD and which side goes to the Stamp Next check the jumper settings on the LCD and refer to its manual to see what it means and what it requires from the Stamp Next go to the Basic Stamp II manual to check out the SEROUT command Specifically check how Tpin Baudmode and OutputData should be configured When all the above are done write a short test program to test the LCD command set 3 3 2 Procedures 1 Complete the hardware connections according to figure 3 Make sure that the LCD is connected to Vcc and GND correctly 2 The other team member checks all the connections before powering up the system 3 In the Basic Stamp programming window edit and run the program Make sure the P
5. C is connected to the Board of Education via the serial cable 4 Unplug the PC serial cable and plug the LCD serial cable to the Board of Education 5 Press button 2 on the keypad check the LED It should flashing once per second The LCD should also continuously display and update the time in second 6 If LED and LCD display is not correct unplug the power source Repeat steps 2 6 until the LCD is displaying correctly Then press button 5 Check the result It should stop the clock and display the elapsed time Edit the program if needed 7 Pressing button 2 again should reset the LCD before beginning the count again Edit the program if needed 8 Measure and tune the accuracy of the stopwatch by comparing it with a watch clock 3 3 3 Documented Source Code Source code deleted 4 Component Price List Components Price Qty Source Basic Stamp II amp Board of Education USD 92 65 1 Parallaxinc Matrix Orbital LCD Display CDN 80 1 HVW tech TIL306 Numeric Display CDN 9 90 1 Meas Lab 4x4 Matrix Keypad CDN 15 1 HVW tech Breadboard CDN 18 60 Digikey 1K Resistor 10k Resistor Basic Stamp II Manual v1 9 pdf format Free 1 Parallaxinc Wires Free lots Meas Lab Wire cutter Free 1 Meas Lab Multi meter 5 Discussion The laboratory exercises had been useful in helping us learn the PBASIC language and getting us used to the Basic Stamp II working environment Through the exerci
6. a fake time bomb etc The list is endless of course 7 Contributions of Each Member Anny Xie Yeow Wei Pang Software Wrote test program for LED Wrote test programs for LCD display and TIL306 Wrote code for LCD using the Wrote code for scanning matrix SEROUT command keypad Hardware Connected circuits according to Checked connections of circuit circuit diagrams before powering up system Implemented LED and keypad Labeled wires and tidied up tests circuit Documentation Laboratory procedures Drew circuit diagrams Tasks hardware used sections Included relevant pictures Title page component price list Abstract introduction appendix discussion and conclusion Documented source codes 8 Appendix 8 1 Referenced Websites http www parallaxinc com http www cim mcgill ca venkat 554 NOTES LAB1 til306 html http www cim mcgill ca venkat 554 NOTES LAB1 til306 pdf htip www hvwtech com Icd htm http www howstuffworks com microcontroller htm http www jameco com Catalog default html htip canada digikey com 8 2 Documented Source Code of Combined Program Deleted THE END
7. boratory Procedures In order to minimize the trouble during each lab exercise before we start we made sure that all the devices were in good condition and that they will perform as expected Basically this involves writing a test program to test the basic functions of the devices LCD and TIL306 A multi meter was also used to test the matrix keypad While doing so we found that one of the columns did not make a connection 3 1 Lab Exercise 1 Turn a LED On and Off in Response To a Keypad Input 3 1 1 Keypad Test If one key is pressed the corresponding row and column will be connected So simply by using a multi meter an ohmmeter in this case we can know which lead corresponds to which row column Also we will be able to know if a connection is actually made Note When using the keypad it should always lie flat on a surface This is to prevent damaging the circuitry within the delicate membrane keypad 3 1 2 LED test This test was to determine the polarity of the LED s leads The diagram of this test is as follow jn aj Connect all the elements on the breadboard except the LED Then plug LED in if it lights up the foot connected to the voltage is the positive polar otherwise it the negative one Normally the longer foot is the positive polar and this was proven in the test 3 1 3 Procedures 1 Complete the hardware connections according to figure 1 Make sure that the LED is connected in the right direction 2
8. getting that right we performed digital outputs to an LED and a TIL806 according to the inputs read from the matrix keypad Finally we interfaced a LCD display using a serial connection and the SEROUT command 1 1 Tasks PBASIC programs have been written to perform the following tasks using above mentioned hardware a Turn a LED on and off in response to a keypad input The initial state of the LED is off when Button 1 on the matrix keypad is pressed flash the LED once per second When keypad Button 4 on the matrix keypad is pressed turn the flashing LED off See figure 7 for hardware implementation b Interfacing a Seven Segment display Initialize the seven segment display TIL 306 to show a blinking cursor Then set it up to display the last key pressed on the matrix keypad See figure 2 for hardware implementation c Implement a digital stopwatch on the LCD When keypad Button 2 is pressed begin flashing the LED once per second and continuously display and update the time in seconds on the LCD When keypad Button 5 is pressed stop the clock and display the elapsed time The next time Button 2 is pressed the displayed elapsed time should be reset before beginning the count again See figure 3 for hardware implementation Turn a LED on and off in response to a keypad input LEF F Li a camlstor Le in marisa with tha r be f P ii 1 r DEC ES PrEEYEEC LE TECE CrmyLirg 25 mm l 1 in ihe mrar Di radii or
9. guage makes it extremely easy to create software for the controller The microcontroller chip can be purchased on a small carrier board that accepts a 9 volt battery and can be programmed by plugging it into one of the ports on a desktop computer See table 1 for Basic Stamp II features RAM 26 bytes EEPROM 2K bytes Max program length about 600 instructions Execution speed 4000 lines sec I O pins 16 Table1 Basic Stamp II Features 2 2 LED This is a commonly used light emitting diode 2 3 Seven Segment Display TIL306 i _ _ TIL3806 seven segment light emitting diode LED displays is produced by Texas Instrument company it contain a BCD counter a four bit latch and a decoder LED driver in a single 16 pin package The feature mechanical data and terminal function can be found in http www cim mcgill ca venkat 554 NOTES LAB1 til306 paf 2 4 Matrix Orbital LCD LCD1621 The LCD used in this lab is the product of HVW Technologies company The introduction user manual operating specifications and mechanical drawing and command set can be found in http www hvwtech com Icd htm 2 5 4x4 Matrix Keypad arney 0a o aooo 50ga eo The keypad used in this lab is also the product of HVW Technologies company It is a4X4 membrane keypad The configuration of the leads is as shown above 2 6 Others Resistors breadboard multi meter wires wire cutter and a computer 3 La
10. ocessors for Mechanical Systems a Turn a LED on and off in response to a keypad input 3 pins were used to experiment with a scanning technique This proves to be useful for part b of 1 output to target is byte flag is either 1 0 initialize flag initialize target initialize pin directions scanning R1 of keypad put pin 5 low put pin 4 high check if Button 1 is pressed continues to scan R2 scanning R2 of keypad now put pin 4 low and pin 5 high check if Button 4 is pressed goto LED_ON only if flag is up continues to scan Rl this section flashes LED set flag up put pin 15 high for 50 milliseconds put pin 15 low for 950 milliseconds continues to scan R2 this section stops LED flag down continues to scan R1 3 2 Lab Exercise 2 Interfacing a Seven Segment Display 3 2 1 TIL306 Tests Connect the GND and the Vcc leads of the TIL306 All the LED s on it should light up If this is not the case bring it to George Dedic or Georges Tewfik to report the problem If all goes well connect the remaining leads as shown on figure 2 and write a short program to pulse the CLK of the TIL306 3 2 2 Procedures 1 Complete the hardware connections according to figure 2 Make sure that the TIL306 is connected to Vcc and GND correctly 2 The other team member checks all the connections before powering up the system 3 In the Basic Stamp programming window edit and run
11. ses we also got to see its programming limitations For example multitasking is not possible and to implement an alternative would make the programming slightly more tedious For this reason the matrix keypad is not responsive when we tried to stop the stopwatch or stop the LED from flashing since the program pauses and does nothing during that 1 second duration Instead it could have gone off to continue scanning for other keypad inputs Due to time constraints that was not implemented in our program We also got the stopwatch to be reasonably accurate In our trials no time was lost or gained in a 10 minute period This could be improved of course if we had let the stopwatch run for 18 hrs 64800 seconds and factored in the time lost gained in the pause command According to our program approximately 33 milliseconds 1000 957 10 were used to scan the matrix keypad The other objectives were accomplished with the successful completion of all 3 laboratory exercises A program that combines all 3 previous programs is attached in the Appendix section 8 2 6 Conclusion We have interfaced the Basic Stamp II I O with a matrix keypad an LED anda serial LCD display We have gained some insights into the programming of a microcontroller The next step to all these is of course to use the knowledge learnt here and implement other cool projects For example a bunch of flickering Christmas tree lights a calculator a Y2K countdown clock
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