COMP 304B Object-Oriented Software Design - Assignment 4

Practical information


This assignment will make you familiar with Statecharts.
The grading scheme is detailed in the behavioural requirements

Upload the AToM3 model file, its bitmap representation, and the compiled file and all the files needed to run the UI application to WebCT and provide links to the bitmap image and to the zip file containing your executable applicatin from your index.html file.
Also include any additional information the corrector might require to correct the assignment.
Your submission should consist of the the html file, the image and (containing the files to run the applciation as well as the AToM3 model).


In this assignment, you will design a Statechart model specifying the reactive behaviour of a Digital Watch (inspired by the 1981 Texas Instruments LCD Alarm Chronograph).

You will first model the reactive behaviour of the watch in the DCharts formalism (a variant of Statecharts) in the tool AToM3. The Statechart simulator SVM (as a plugin of AToM3) will allow you to check, by means of simulation, whether your model behaves according to the requirements. Note that it is good practice to start modelling and simulating small parts of the desired behaviour in isolation. These can be saved and later loaded to build the full solution Statechart.

The model (saved as and its visual representation must both be included in your index.html solution page. The visual representation can be obtained by "print-screening" the AToM3 model to a bitmap image file called DigitalWatchStatechart_DCharts_MDL.png.

When you are satisfied with the simulated behaviour, you are ready to build a Digital Watch software application. The application's reactive behaviour will be generated from the Statechart.

The software application ( is composed of a static component, a controller and a dynamic component.

The static component ( implements the visual aspects of the watch such as buttons, the display and the Indiglo light and organizes them into a graphical user interface (built using Tkinter, the standard Python interface to the Tk GUI toolkit).

The dynamic component ( will be automatically generated from your Statecharts model.

The communication between the static and the dynamic components is handled by the controller (found in User events such as button press/release are passed from the GUI to the Statechart (as strings) by the controller. Conversely, the Statechart modifies the (visual) state of the GUI by invoking the controller's methods.

Note that the Statechart receives a reference to the controller object as a parameter of the start event when, at application startup time, it goes from its initial state Setup to the state Running.

Behavioural Requirements

  1. (10%) The time value should be updated every second, even when it is not displayed (as for example, when the chrono is running). However, time is not updated when it is being edited.
  2. (10%) Pressing the top right button turns on the Indiglo light. The light stays on for as long as the button remains pressed. From the moment the button is released, the light stays on for 3 more seconds, after which it is turned off.
  3. (10%) Pressing the top left button alternates between the chrono and the time display modes. The system starts in the time display mode. In this mode, the time (HH:MM:SS) and date (MM/DD/YY) are displayed.
  4. (20%) When in chrono display mode, the elapsed time is displayed MM:SS:FF (with FF hundreths of a second). Initially, the chrono starts at 00:00:00. The bottom right button is used to start the chrono. The running chrono updates in 1/100 second increments. Subsequently pressing the bottom right button will pause/resume the chrono. Pressing the bottom left button resets the chrono to 00:00:00. The chrono will keep running (when in running mode) or keep its value (when in paused mode), even when the watch is in a different display mode (for example, when the time is displayed).
    Note: interactive simulation (in AToM3) of a model containing time increments of 1/100 second is possible, but it is difficult to manually insert other events. Hence, while you are simulating your model, it is advisable to use larger increments (such as 1/4 second) for simulation purposes.
  5. (10%) When in time display mode, the watch will go into time editing mode when the bottom right button is held pressed for at least 1.5 seconds.
  6. (20%) When in time display mode, the alarm can be displayed and toggled between on or off by pressing the bottom left button. If the bottom left button is held for 1.5 seconds or more, the watch goes into alarm editing mode. This is not an example of good User Interface design, as going to editing mode will also toggle on/off and that may not be desired. It is however how the 1981 Texas Instruments LCD Alarm Chronograph works. The first time alarm editing mode is entered, the alarm time is set to 12:00:00. The alarm is activated when the alarm time is equal to the time in display mode. When it is activated, the screen will blink for 8 seconds, then the alarm turns off. Blinking means switching to/from highlighted background (Indiglo) twice per second. The alarm can be turned-off before the elapsed 8 seconds by a user interrupt (i.e.: if any button is pressed). After the alarm is turned off, activity continues exactly where it was left-off. Note that after the alarm finishes (flashing ends), the alarm is un-set (so it will not go off the next day at the same time).
  7. (20%) When in (either time or alarm) editing mode, briefly pressing the bottom left button will increase the current selection. Note that it is only possible to increase the current selection, there is no way to decrease or reset the current selection. If the bottom left button is held down, the current selection is incremented automatically every 1/2 second. Editing mode should be exited if no editing event occurs for 5 seconds. Holding the bottom right button down for 2 seconds will also exit the editing mode. Pressing the bottom right button for less than 2 seconds will move to the next selection (for example, from editing hours to editing minutes).

Interface provided by the controller

  Returns the current clock time.

  Returns the alarm time set. 

  Checks if the alarm time set is equal to the current
  clock time. If so, it will broadcast the "alarmStart" event  
  to the statechart and return true.  Otherwise, it returns false.
  Note that checkTime() does not care/check whether the alarm
  has been set "on". 
  Note: On some OS, the "alarmStart" event may not broadcast, you will need to encode this broadcast in your statechart.


  Redraw the time with the current internal time value.
  The display does not need to be cleaned before calling
  this function. For instance, if the alarm is currently
  displayed, it will be deleted before drawing the time.

  See refreshTimeDisplay()

  See refreshTimeDisplay()

  See refreshTimeDisplay()  

  Resets the internal chrono to 00:00:00.

  Selects the leftmost digit group currently displayed on the screen.
  Increases the currently selected digit group's value by one.
  Select the next digit group, looping back to the leftmost digit group when
  the rightmost digit group is currently selected. If the time is currently 
  displayed on the screen, select also the date digits. If the alarm
  is displayed on the screen, don't select the date digits. (to simplify the

  Increase the time by one second. Note how minutes, hours, 
  days, month and year will be modified appropriately, if needed
  (for example, when increaseTimeByOne() is called at time
   11:59:59, the new time will be 12:00:00).

  Increase the chrono by 1/100 second.

  Turn on the display background light

  Turn off the display background light

  Flag the alarm to be on or off.
Events sent to the Statechart (as strings):

(due to button press)

- topRightPressed
- topRightReleased
- topLeftPressed
- topLeftReleased
- bottomRightPressed
- bottomRightReleased
- bottomLeftPressed
- bottomLeftReleased

(generated by checkTime() if current time == alarm time)

- alarmStart

Starting point

The archive contains a very simple example to get you started. The starting point Statechart is reproduced here

The Models/DCharts/ folder in the central AToM3 installation contains some small examples demonstrating various features of Statecharts. The Models/DCharts/TrafficLight/ folder contains the small traffic light example.

Practical information

It is good practice to model/simulate different parts of the overall solution in isolation (bottom-up design). You can save them in different files and later load them into a combined model.

The scc Statechart compiler tries to produce speed-optimized code. This, at the expense of memory used. When you use too many orthogonal components this will lead to synthesized code which cannot be compiled/run.
When you generate the code directly from AToM3, it produces two files: the .des file and a file. The content of the latter should be put in

AToM3 is installed on the Trottier lab machines and can be started with /usr/local/pkgs/atom3/ or its alias atom3.
You will find some example models in the central Models DCharts directory (Models/DCharts/). This is a good place to find examples of the [AFTER()], [EVENT()], etc. macros.
The svm simulator is installed in the External/ directory of the AToM3 central installation. It is available as a plugin from AToM3. The scc StateChart Compiler can be found in svm's installation directory and can be started with /usr/local/pkgs/atom3/External/svm-0.3beta3-src/scc. The script calls scc with the appropriate arguments.

There is extensive documentation on SVM and SCC. This is for example where you will find detailed information on macros (including on how to write your own). For those interested in more in-depth information on SVM and SCC, have a look at Thomas Feng's M.Sc. thesis.

It is possible to install AToM3 and SVM/SCC on your own computer. They should run on (variants of) Windows, Linux, and Mac OS X (as long as Python/Tkinter is installed). Note that due to recent problems with Tkinter, there may be problems on Mac OS X. You need to download the latest version of AToM3 from It already contains the External Utility Pack for SVM/SCC.

Eugene Syriani Winter Term 2010.