Texas Instruments TI-83 Plus Graphing Calculator

Important information

Texas Instruments makes no warranty, either expressed or implied, including but not limited to any implied warranties of merchantability and fitness for a particular purpose, regarding any programs or book materials and makes such materials available solely on an “as-is” basis.

In no event shall Texas Instruments be liable to anyone for special, collateral, incidental, or consequential damages in connection with or arising out of the purchase or use of these materials, and the sole and exclusive liability of Texas Instruments, regardless of the form of action, shall not exceed the purchase price of this product. Moreover, Texas Instruments shall not be liable for any claim of any kind whatsoever against the use of these materials by any other party.

INTRODUCTION

The User Interface (UI) guidelines contained in this document are for the TI 83 Plus calculator.

Using these guidelines will make the development process of new calculator applications easier by creating a frame of reference from which to start. And more importantly, these guidelines will make it easier to optimize the interaction between the user and the calculator.

These guidelines are not hard and fast rules. They are only recommendations. Each application has its own unique needs, and in many cases, modifications to the guidelines may be needed to create a useful application.

GENERAL THOUGHTS

When designing the user interface for new calculator applications, keep in mind that the user will already be familiar with the basic UI elements used in the calculator’s built-in functions. Starting a design with these familiar elements makes it easier and quicker for end-users to start using the calculator application. This will also reduce the complexity of the instruction manuals and reduce or eliminate after-purchase support.

However, it is important to note that improvements can and should be made to the basic UI elements. The basic UI elements are just that: basic. They do not cover all possible functions and operations that would be needed in a new application. Changes and modifications to these basic UI elements or the introduction of new UI elements should be considered when they provide a perceived benefit to the end user.

Analogies to existing everyday life activities are good starting points for creating an application’s user interface. Fortunately, most TI 83 Plus calculator users are computer literate; windows, function keys, messages, and dialog boxes are familiar concepts. Thus, the computer is a good analogy when creating a new user interface. While the calculator does not have a pointing device (mouse), it does have a highly effective cursor control system (arrow keys). The screen resolution (64 by 96 pixels) is a fraction of its computer counterpart. Therefore, one needs to be careful when using graphical elements such as icons.

An iterative design process with a feedback loop is one of the most efficient ways to optimize a calculator application’s user interface. The steps are straightforward:

• Evaluate the function or operation that needs to be performed
  It is often useful to make a list of every function that the application needs to provide, and then write out the functions in an active expression. E.g., the user selects the type of curve from a list of four choices: up, down, left, and right. Grouping functions into like or similar activities can highlight common activities and often give structure to disparate tasks.
• Simulate the user interface. This can be as simple as creating storyboards on paper or actually coding the desired function to run on the calculator. Obviously, a real simulation on a calculator eliminates some of the testing variability, but this is usually a costly and time-consuming effort.
• Test with end-users. There are no substitutes for this step in the process. There are many ways to perform these tests. Some can be as simple as a one-on-one interview, or as complex as a hundred-user beta program.
• Analyze the results and make necessary changes. This step in the process can be the most challenging. Tradeoffs and prioritization of the functions need to be made, and often without enough data from step 3.
• Go back to step 2.
  There are no rules for how many times a user interface design must go through this feedback loop. Time and resource constraints usually dictate when and if more changes are needed.

TERMINOLOGY AND CONVENTIONS

• In order to effectively communicate the user interface design guidelines, the following conventions and terminology are used.
• Application – a “signed” executable software program of low-level instruction code that runs in the flash memory space on the TI 83 Plus calculator.
  • ASM – a low-level executable software program that runs in the static RAM memory space on the TI83 Plus calculator. This is sometimes referred to as an “assembly program.”
  • Program – a set of commands that the TI83 Plus calculator executes sequentially as if you had entered them right from the keyboard. This has also been referred to as “Calculator BASIC.”
  • User Data Archive – calculator data or an ASM that is stored in the flash memory space on the TI 83 Plus calculator. This is somewhat analogous to a hard disk on a PC.
  • Hard key – a predefined key on the calculator. In this document, they are shown as they appear on the calculator e.g. z and Í. The second functions are shown in brackets, in upper case letters e.g. y [QUIT]. The cursor keys will be shown as follows: up }, down ƒ, left | , right ~.
  • Soft key – one of the keys on the top row when used in conjunction with a graphic on the bottom of the screen. Soft keys will use the same notation as the hard keys, except that they will use lowercase letters, e.g., [esc] and [quit]. Positions of the soft keys will be denoted by the abbreviations: F1, F2, F3, F4, F5.
  • Home screen – the primary screen of the calculator used to enter instructions for execution, and expressions to evaluate.
  • Pixel location – the pixel numbering system is similar to that used on the Pxl-On (row, column) function where the row numbers are from 0 through 63 and the column numbers are from 0 through 95. The upper left pixel is (0,0) and the lower right pixel is (63, 95).
  • Standard font – this is the 5 x 7 pixel font used by the built-in calculator functions. The complete list of characters is shown in Appendix A
  • Small font – this is the 3 x 5 pixel font. The complete list of characters is shown in Appendix B.
  • Continuous scrolling – when the user presses a cursor key, the resulting action will advance to the next item, choice, element, etc. When the last item is reached, it will advance to the first item. There is no end; it acts like a continuous loop.
  • End scrolling – when the user presses a cursor key, the resulting action will advance to the next item, choice, element, etc. When the last item is reached, it will stop at that item.
  • Auto-repeat – pressing and holding down a key will automatically repeat the keypress at a constant rate.
  • Workspace – the area above the soft key legends

FAQs

User Guide

References

• User Manual