CTEC1630 Embedded Systems Design

A design course concentrating primarily on building skills to exploit the technology of the microcontroller (MCU). Students will study the architecture of a typical microcontroller (the PIC 18F family from Microchip), basic programming, debugging, and testing techniques for assembly-language programs. As well, devices such as LCDs and matrix keypads will be interfaced to these MCUs. The course culminates in a term project designed, constructed, programmed, and tested by the student. The project serves as a vehicle in which students examine the identification of requirements for a system as well as develop project management skills.

At a final-term project demonstration, Darryl demonstrates his project to VP Martha Casson. Darryl's project involved retrofitting a Scamps^tm toy with a PIC microcontroller allowing full Win-32 control of the toy. The microcontroller was tied into existing circuitry including an H-bridge used to control the motor and various sensors in the toy. Interactive responses can be programmed via the Windows-based front-end program. Envisioned applications include use as a learning tool for emotionally troubled children.

Pictured here is Krish beside his project which was to build the controller for a spectrophotometer. While the mechanical system of the spectrophotometer was impeccable it lacked a scanning and control system. Krish used a PIC16F877 processor to control the step motor of the unit and acquire data from the photomultiplier feeding it back to a PC running a Win-32 program written in C++. The finished system will be used in the lab by students in the Photonics program.

Prerequisites

CTEC1530 MicroComputer Design (80x86 architecture, assembly language, and interfacing). This prerequisite is extremely important since it is assumed that the student has prior knowledge of assembly-language programming, constructs, and procedures such as assembling and linking code.

Co-requisites

CTEC1631 Digital Signal Processing must be completed in tandem (or after) this course since it utilizes the same development tools as this course. The use of the IDE, a skill learned in this course, is applied in CTEC1631.

This course is offered as part of the 'hardware stream' of courses in the Computer Engineering Technology (3 year, co-op) Program at Niagara College.

Embedded Design with the PIC18F452 Microcontroller by John B. Peatman, Prentice-Hall; ISBN 0-13-046213-6

Evaluation ...

There will be two term tests valued at 25% each plus Labs valued at 20% and a major term project valued at 30%. Alternatively, an optional practical final may be included into the marking scheme in which case the theory mark will consist of a final exam valued at 25% with the two term tests worth 12.5% each. Regardless, students must pass the theory (testing) and practical (lab/assignment) portions of the course separately in order to pass the course. Failure to pass either portion (theory or practical) will result in a maximum final mark of 45%.
Midterm #1 on Thursday, Oct. 15, 2009 in class
Covering basic PIC programming, memory model and data representation, code timing, and timers
Midterm #2 on Wednesday, Nov. 18, 2009 in class
Covering interrupts, use of the LCD, USB concepts, software safety

Check your marks and registration status here (Ready - 2009F)

• Monday, Sept. 21, 2009, in class: Project Proposal
  a short document outlining the basic premise of the project, basic hardware to be used, and role of the microcontroller. An example may be found in the Project Submissions document under course notes.
• Monday, Oct. 5, 2009, in class: Hardware Design
  a schematic and parts list for the project. Parts requests submitted after this date are not guaranteed to arrive in time for further project development. An example may be found in the Project Submissions document under course notes.
• Monday, Nov. 2, 2009, in lab: Hardware Demonstration
  "Bring working hardware or bring a drop/add form". By this date students must have put a substantial effort into completing a good portion of the project including assembly and testing of any required hardware. The demonstration consists of hardware as well as low-level driver software to demonstrate the hardware is working.
• Monday, Nov. 30, 2009: Final Project and Report Due
  a complete project report. An example may be found in the Project Submissions document under course notes. If submitted late (but after a successful project demonstration on the 30th), only the report is penalized at 10% per day late, zero after five days late.

For 2009F ...

• Lab 1: The IDE development environment including the ICD debugger
  Use of the IDE development environment, programmer, and debugger are examined in this introductory laboratory. Simple assembly-code programs (e.g. a light chaser) will be assembled, modified, and programmed into a processor and the ICD debugger will be used to step-through and debug these programs. The environment will be the same in the DSP course (CTEC1631) however a more advanced assembly language (ASM30) will be used in that particular course.
  Due (with demonstration) on Monday, Sept. 28, 2009 at 10:30 a.m.
• Lab 2: "Spirit Level ..." a reaction-time tester
  A reaction-time tester, originally intended for use as an intoxication meter, is constructed using pushbuttons for user input and an LED bargraph for output. All delays are effected via the use of on-chip timers.
  Due (with demonstration) on Monday, Oct. 19, 2009 at 10:30 a.m.
• Lab 3: Graphics Programming of the LCD
  An LCD is programmed to display moving graphics using the bitmapped character-generator RAM in the device - in this case a PacMan^tm which moves across the display. Concepts learned here may prove useful in your project.
  
• Lab 3: An interrupt-driven Real Time Clock
  A real time clock (displaying hours:minutes:seconds on the on-board LCD) is implemented using an interrupt-driven timer. Concepts applied in this lab include use of the timer hardware, programming an ISR, and use of the LCD (which also requires new LCD functions to be written).
  Due (with demonstration) on Monday, Nov. 9, 2009 at 10:30 a.m.
• Lab 4: Use of the serial port to communicate with a PC
  The serial port will be programmed to receive and transmit to a PC. Receive functions will be handled by an interrupt service routine which will buffer incoming characters. When a full line is received (terminated by a return character) the entire line, encoded in ROT-13 is transmitted back to the PC.
  OPTIONAL lab: Due (with demonstration) on Monday, Nov. 30, 2009 at 10:30 a.m.

The two-hour lab period, each Monday, is a general-purpose tutorial session to be used for debugging labs as well as specific discussions around projects. It is not anticipated that labs will be completed during the lab period as labs will generally consume more time than available during this period. Attendance at the lab period IS required when a lab or other assignment is due (unless it is handed-in ahead of time). Aside from this period, project discussions or assistance with a lab may be arranged with the professor during any of the posted office hours (posted on the EL panel on the office door in L-17) ... there is generally NO time available immediately before or after lectures for this.

Project

A major portion of this course is a microcontroller-based project. This project represents a typical design and construction project given to a new technologist. It consists of designing and constructing the project, testing it to ensure it meets specifications, and writing-up the entire project in a report.

The project is to be chosen by the student from a list of acceptable topics. If a student has a particular idea not on the list, discuss it with the professor. Only ONE student will be allowed to choose each topic on a first-come, first-taken order. Choose a topic which is of interest to you: If you are interested in writing an interpreter then the micro-PLC project might be of interest to you. If you like communications, perhaps a networking project is a good choice.

Each lab incorporates important principles such as interfacing the MCU to a 16 char by 2 line LCD display and matrix keypad, data acquisition, real-world interfacing, etc. Software will consist of the actual control task programming in RISC assembly language. Software must be reliable, functional, as well as user-friendly.

Timeline 2009F (the project is to be completed concurrently with labs in this course):

• Week 1: Introduction to the project and requirements
  Students will begin by examining the capabilities of the microcontroller and possible topics of personal interest. Searches of the web will likely help locate possible topics. If a project is not chosen by the beginning of week 3 one will be assigned to the student.
• Week 3: Preliminary Project Selection is due [milestone]
  Sign-up will begin on week 2. If you have an idea, simply ask the professor.
• Week 4: Project Acceptance (Contingency)
  Students with rejected project ideas must have a new idea by week 4.
  Week 4: Hardware design Begins
  Gather data on available parts and begin a preliminary design.
• Week 5: Hardware design (schematic and parts list) due [milestone]
  A detailed machine-drawn (CAD) schematic showing the microcontroller and all required external hardware. Included in this requirement is a detailed parts list with DIGIKEY part numbers so that these may be ordered before project assembly begins. Approx. 10% of total project marks are assigned to the hardware design.
• Week 6: Parts Order received
  Week 6: Hardware Build Begins
  Week 6: Software Design Begins
  Prototyping, both hardware and software (low level), can begin.
• Week 8: Hardware design complete
  Hardware redesign, if required, as well as software test programs.
• Week 9: Hardware Demonstration [milestone]
  Week 9: Software Build
  Demonstrate the hardware working. Low-level software functions may also be required in order to prove hardware is working and build upon these when developing the main code. Approximately 15% to 20% of total project marks depend on this demonstration. Software design and coding of the main program begins.
• Week 12: Software Complete
  Week 12: Report Begins
  Contingency time to finalize software ("fine tuning"). With software completely running, compose the project report.
• Week 13: Project Report Due, Demonstration [milestone]
  Projects will be demonstrated during the lab period in L17. Project reports are due as well.
• Week 14: Parts Return
  PICPROTO boards are to be returned to Central Supply, individual parts to the professor. A refund of the deposit will then be mailed to your last current address (so be sure to update this with the registrar).

The popular Nighthawk brand of CO detector uses a PIC16C622 as it's brain. This processor, seen highlighted in the right photo, provides an on-chip ADC to convert analog values from both the electrochemical cell (which senses the presence of CO) and a thermistor (which senses ambient temperature) into binary values. The amount of CO is then computed in the PIC and is displayed on the multiplexed LEDs. This application illustrates a major advantage in the use of microcontroller-based designs in reducing component count. If built with conventional electronic components and discrete logic circuitry the unit would hardly fit into a suitcase let alone a small plug-in unit.

Past Projects

Past projects include:

• Robotics projects ranging from a robotic arm to a small 'mouse' type robot
• Adapting a Nintendo Power Glove ^tm to operate as a PC mouse
• Security systems for both vehicles and dwellings
• IR remote-control applications including 'learning' remotes
• Data acquisition devices
• A video Tic-tac-toe game which generates NTSC signals in real-time
• Lab equipment including a serial-EEPROM programmer and a spectrophotometer
• A PC-controlled Furby^tm with a Win-32 front-end
• A computer-controlled Beer-brewing setup

Note: Each project incorporates a demonstrable milestone - essentially a check to ensure the hardware design is functional - to which marks will be assigned. Hardware must be demonstrated as working during the lab period on week 9 allowing time for redesign along with component ordering lead time. This mark will count for up to 17% of the project mark so it is imperative that the student complete the hardware design on time.

SD Card Datalogger
An SD card is wired to a PIC controller and, using the on-chip SPI interface, is used as a massive storage element allowing huge amounts of data to be logged. The data can be logged from a serial port and could be written to the SD card in a PC-compatible format (e.g. FAT-32) or could be acquired via a parallel interface and uploaded to a PC via the serial port: numerous options exist here. The system must be capable of logging over 256 MB of data points proving the capabilities of the SD-card. Note that the SD card uses 3.3V so the use of some interface circuitry (from simple resistors to a level-converter chip) is required. Demonstrable Milestone: Ability to write a byte of data to the SD card and read it back.

A Voice-activated Mouse
A serial mouse which uses a voice-recognition module allowing the user to say commands such as "Mouse Up", "Mouse Right", or "Mouse Click". Could be used as an aid for the handicapped. The device must emulate a serial Microsoft mouse and can utilize the voice recognition module from Sensory, Inc. Demonstrable Milestone: Plug it into a PC and have it recognized, and operate, as a serial mouse.

An Infrared remote-control Mouse
A serial mouse which uses a regular remote control. The number keys may hence be used to move the cursor and four other keys for 'click' and 'double-click'. IR signals may be received using a standard IR detector/demodulator module and any desired protocol could be used. Intended usage is for presentations (e.g. PowerPoints). The device must emulate a serial Microsoft mouse. Demonstrable Milestone: Plug it into a PC and have it recognized, and operate, as a serial mouse.

A Dial-In Home Monitor
Using an inexpensive external modem, this system allows a remote user to dial-into a house and check the status of home security, temperature, etc. using a remote terminal package. A "second ring" scheme may be used to allow concurrent use with an answering machine. On connection, the user should be provided with a simple menu of options which includes checking the status of various home-control systems as well as display temperature in the house. This project involves use of communications protocols (e.g. "ATDT" codes) and serial communications. Demonstrable Milestone: Ability to communicate with the modem and make connection with a remote terminal.

A Voice-synthesized Dial-In Home Monitor
This system allows a remote user to dial-into a house and check the status of home security, temperature, etc. all accessed using a regular touch-tone (tm) phone. A "breakthrough-code" scheme may be used to allow concurrent use with an answering machine. On connection, the user must provide a simple passcode and the status of various home-control systems, as well as temperature in the house, will be spoken via a voice synthesizer such as a General Instruments SPO-256 chip. This project involves interfacing to the telephone line, DTMF reception (via, for example, an 8870 chip), and voice synthesis. Demonstrable Milestone: Ability to read DTMF codes from a line and generate a voice message (e.g. "Test 1,2,3") via the synthesizer.

Printer emulator
Some older pieces of test equipment (e.g. the college's logic analyzers) can only use an Epson printer as an output device. This emulator plugs-in between the piece of equipment (via a Centronics printer connector) and a PC (via a serial or USB connection), emulating an Epson printer and converting the output for display on a PC via a Windows program (which is also part of this project). Ultimately, then, output from the test equipment which would have been printed would then appear in a Window (with the ability to cut and paste into any other Windows application). Demonstrable Milestone: The ability to sample and display (on an LCD or a serial connection) 'raw' printer data showing received codes

A Handheld Logic Analyzer or Oscilloscope
The PIC18F452 has a good deal of memory and, combined with a true bitmapped LCD (with an interface different than the normal LCD employed in class) can be used to build a one-chip logic analyzer or simple oscilloscope. The LCD must display four channels simultaneously (or a single analog channel) and must be programmable for sample time and trigger. Timing may be accomplished by using an internal timer and the unit should be capable of at least 200KS/s. Demonstrable Milestone: Display of a 'canned' waveform on the LCD Display

A Video Logic Analyzer
Running at 40MHz, the 18F MCU is capable of at least 1 MSample/sec across eight channels (if desired, the student may use a 30F6012 DSP processor for faster performance and more trace memory). Samples are then displayed as eight parallel traces on a dedicated display panel such as a Finlux EL flat-panel display which features separate vertical and horizontal synchronization signals (see the professor's flat panel driver for details). User selectable parameters include sample rate and trigger channel. A commercial model may be seen here. Demonstrable Milestone: Generation of traces (using 'canned' data such as a square wave) on the video display

A USB-based digital Strip-chart Recorder
Using the on-chip ADC this device samples analog channels at programmable fixed time intervals and stores data in a large, external, serial EEPROM. Time intervals and number of channels are programmed via a Win-32 front-end PC program. Data may then be downloaded to a PC via a USB connection and graphed on a Win-32 program which allows scaling of axes. The graph may then be pasted into other Windows applications. An 18F4550 processor may be employed in this project (instead of the usual 18F452) since it features an on-chip USB transceiver. This is a challenging project involving a good bit of student research. Demonstrable Milestone: USB connection verified on a PC

A Spectrophotometer Interface / Digital Strip-chart Recorder
Similar to the above project, uses the on-chip ADC to sample the analog input at programmable fixed time intervals and stores data in memory. Time intervals are programmed via a Win-32 front-end PC program (the scan rate is programmed on the machine and must be entered via the PC front-end as well) and the device must interrogate a fixed input to skip filter-change intervals. The output from the machine can be seen here - the top line is the analog input which represents % transmission and the lower line shows when the scan is active (when low). The scan starts on the left side and continues until a filter change occurs at which point timing must be interrupted until the scan begins again. Data may then be downloaded to a PC via a USB or serial connection and graphed on a Win-32 program which calibrates axes. The graph may then be pasted into other Windows applications. A commercial device, similar to this one, is employed in V14A and may be seen there - this device lacks the ability to halt recording while filter changes occur. An 18F4550 processor may be employed in this project (instead of the usual 18F452) since it features an on-chip USB transceiver. Demonstrable Milestone: USB connection verified on a PC

Model Railroad Block-detection and signalling
In a traditional approach, each block on a model railroad has a twin-tee current detector wired to up to six signals on either side of that block ...wiring is quite a mess. In this new approach a small network will be used to convey information about block occupancy to signals and operator so that wiring consists of a simple two wire bus onto which all devices are attached. The best network protocol for this application is an RS-485 multidrop with the on-chip serial port used for serial Rx/Tx. With an appropriate protocol, signals can be fully automated and autonomous with signal indication depending on occupied blocks as well as position of switches on the track. The proposed system would have each block detector 'announce' its status, when a block changes state to become occupied or free, on the network and have signals 'listening' for such changes. A table structure inside the signal processor would then determine the correct indication based on occupancy of various blocks. The professor has a document outlining a proposed system of this type but the student will be required to research the operation of ABS block signals (a good start might be here where signals are examined from a modelling perspective) as well as basic model railroad electronics.

Other Possibilities ...

• Home Alarm System using a remote keypad which communicates via a serial link
• Garden Watering System which waters the garden each day, however it monitors actual soil moisture levels using a resistive or galvanic probe to avoid over-watering

Other Goodies ...

I have available in my collection of parts the following which might be useful for a project:

• A voice-recognition module which provides discrete output when a learned word or phase is recognized. For example output 1 is brought high when the word "One" is spoken. Might be good for a voice controlled ____.
• An SPO-256 voice synthesizer chip which can produce essentially any spoken word by producing the allophones that compose it. Might be useful for a talking ___.
• Telephone line interface equipment including DTMF decoders (8870). Might be useful for a dial-in monitor or controller.
• Step Motors, useful for a precision motion project like an X/Y table for a laser cutter, etc.
• A Playstation/Nintendo joystick (which uses a serial protocol
• IR remote-control receivers and emitters. Find a unique application for this technology, though, which has not been 'done to death'.
• IR Proximity sensors which provide an analog output proportional to the distance an object sits from the sensor (up to 30cm).
• Humidity and Light sensors.

Quick Start Guide A guide to getting "up and running" with the PICPROTO board used in our labs (Password-protected PDF)
Debugging with the ICD-2 A guide to using the ICD-2 as a debugger (Password-protected PDF)
I/O Hardware 101 A look at CMOS and TTL I/O (Password-protected PDF)
Programming Constructs and Timing Writing delay functions and how to count clock cycles for program execution (Password-protected PDF)
How NOT to Program A few tricks and traps NOT to fall into when writing PIC code (Password-protected PDF)
Nixie Thermostat A complete project used as an in-class example, with project notes for guidance
Temperature Alarm Design Example A walk through the entire design process of a small alarm system. Note: Based on an older 16F84 PIC chip no longer employed in this course
Temperature Alarm The complete project including downloadable code. Note: Based on an older 16F84 PIC chip no longer employed in this course
Carillon Project a description of a hypothetical project which addresses the issue of project complexity
Software Safety (PPT, Password Protected ZIP) the in-class presentaton on software safety.
Project Submissions outlines the contents of documentation required for the project
Project Marking Scheme the marking scheme for the project
Final Exam Notes outlining procedures required and allowed aids
USB-101 an example of a PIC USB application (Logic Analyzer) NEW

The following are LINKS to web sites which feature microcontrollers. Some sites allow the downloading of code and designs which may be useful to students in this course.

Microchip Inc. ... The company which produces the PIC controller This site features datasheets and maintains a download library of code for PIC microcontrollers.
PICBOOK.COM The site which accompanies the textbook we use. Example code and resources available here.
MAXIM Semiconductor Inc. This site features datasheets for the MAX232 RS-232 transceiver chip
Circuit Cellar INK The folks who give us the class set of magazines each month. Features an ftp site with code from magazine articles available for download, etc.
LCD SIMULATOR allowing prototyping of commands
TeraTerm Pro a simple terminal emulator for a PC
Therac-25 Accident Investigation a paper by Nancy Leveson on the safety of software employed in the infamous therapy machine
Therac-25 Accidents the original paper by Levenson as published by the IEEE in Computer, July 1993
USB In-A-Nutshell from beyondlogic.org, a good introduction to the hardware and protocol involved.

The World's Smallest Web Server Running on an 8-pin PIC processor in about 0.5K words of program memory.
The Furby Autopsy Site A fine example of a microcontroller application
Bob Blick's Projects All of which use a PIC. The most interesting is the spinning clock

DISCLAIMER: All code and examples are copyright Niagara College 1997-2007. This information is intended for suggestion only and may be superseded through updates. Use of this code in any commercial application is forbidden. Code and examples are provided without warranty and Niagara College and the author assume no liability whatsoever with respect to accuracy of information, use of such information,or infringement of patents arising from such use or otherwise. No licences are conveyed implicitly or otherwise under any intellectual property rights.

Example PIC Assembly Code:

SampleAsmFile.ASM UPDATED 2009 An example file which blinks a single LED based on an 18F452 processor. Use MPLAB IDE, open a new project, and add this file to the source file list. To program the microcontroller and run the code, use the ICD-II debugger. This file was updated to use the new CONFIG directives ... assumes a crystal oscillator.
Counter.ASM UPDATED 2009 An example file which turns the LED display into a binary counter. Uses new CONFIG directives.
LCD Test for the 18F452 chip in a PICPROTO-II board. Also demonstrates use of tables.
Simplified P1.ASM A simplified version of Peatman's P1.ASM program which runs on the PICPROTO board and omits all interrupt code. Use the project wizard, select 18F452 processor, and connect an LED to RB0.
Interrupt-driven P1.ASM A version of Peatman's P1.ASM program which uses interrupts for simplicity and accuracy.
Example UART setup code For the 18F UART.
Example EEPROM code allowing storage and retrieval from the on-chip EEPROM.
Example Binary-to-BCD code allowing display of a binary number on the LCD.
Generic Interrupt Code add to the template when using interrupts.
Strings using the computed goto (old) method. Nowadays, use TABLES!

PIC PROTOBOARD II SCHEMATIC (in AUTOCAD .DXF Format) The complete schematic for the PIC proto board used in labs
PIC PROTOBOARD II SCHEMATIC (in AUTOCAD .DWG Format) The complete schematic for the PIC proto board used in labs
PIC PROTOBOARD II SCHEMATIC (in JPEG Format) The complete schematic for the PIC proto board used in labs
PIC PROTOBOARD UPGRADE SCHEMATIC (in JPEG Format) Showing the PIC16F877

SCOPE UTILITY PC-side utility to allow download of images from the TDS digital scopes used in the lab. Password Protected ZIP

2001 Fall Midterm for practice, the complete WORD document. Note that the processor employed was the older 16F84 however the questions will give you an idea of what to expect. Password Protected ZIP (Password given in class)
Midterm 2 Questions for practice. The test typically consists of one small question on interrupts (which may well involve the UART or TIMER), one on Strings/Tables/Indirect memory access, and a major control programming question of the type seen here. Password Protected PDF.

Contact:

For this course ...
Professor Mark Csele
Telephone (905) 735-2211 x.7629
E-Mail: (Be sure to include 'Computer Technology' in the subject line to avoid deletion by an anti-spam filter)
NOTE that this course, with an intense lab component, is not offered by distance ed nor any other mode of delivery. Niagara College does NOT offer student internships to students outside the regular college system.
URL: http://technology.niagarac.on.ca/people/mcsele

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