Texas Instruments TI-83-Plus User Manual

Chapter 3: Application Development Process 123
TI-83 Plus Developer Guide Third Release May 28, 2002
The Hello Application
TI has provided a sample application called Hello. The source for this application is in
the file hello.asm. Open this file in a text editor and look at it to get a general idea of the
main structural elements. The following sections address these elements.
Accessing System Resources
The program begins by including the TI83plus.inc file. This file is provided by TI. This file
includes constant definitions, macros, and system routine entry point definition needed
to use system resources.
Application Headers
The most unique thing about the TI-83 Plus application source code is the long set of
data that begins the file. This data is known as the application header. The application
header contains information used by the calculator operating system when the user tries
to run the application. The operating system uses this information to determine the app
name and whether a user is permitted to use it. A valid header must be present as the
first data in the source file, prior to any executable statement, in order for the app to run
properly.
Header Creation
The header in the hello.asm file can be used for any single page application.
Calling System Routines
On the TI-83 Plus there are a number of built-in system routines available for an
application to use. These routines can not be called directly using the standard Z80 call
instruction. In order to call a system routine, you must use a statement of the form:
B_CALL routine
In this example, routine is the name of any system routine. B_CALL is a macro defined
in the system include file.
Accessing System Variables
Certain fixed locations in RAM are defined for system code usage. The contents of
these locations typically affect some standard system behavior. System routines
sometimes use the variables, so they are in effect parameters to the system calls. To
access one of these variables, you use its symbolic name (e.g., curRow). The variable
names are defined in the system include file, TI83plus.inc.

Texas Instruments TI-83-Plus Specifications

General

Display Type	LCD
Display Resolution	96 x 64 pixels
Power Source	4 AAA batteries
Programming Language	TI-BASIC, Z80 Assembly
Backup Power	CR1616 or CR1620 lithium battery
RAM	24 KB
Processor	Zilog Z80
Weight	7.4 oz (210 g) with batteries
Dimensions	7.3 x 3.5 x 0.9 inches

Summary

Introduction

Conventions Used in this Guide

Defines conventions for program text, syntax, and optional parameters in guide examples.

Purpose of this Guide

Explains the types of programs that can be created and the guide's focus on Flash ROM apps and RAM assembly programs.

TI-83 Plus Specific Information

ARCHITECTURE

Describes the TI-83 Plus architecture composed of several layers: Hardware, Drivers, Tools, and Programming.

HARDWARE LAYER

Covers the Zilog Z80 CPU, RAM, and Flash ROM components of the TI-83 Plus unit.

Z80 RAM Structure

Explains the 32K RAM partitioning into areas like System RAM, User RAM, and Floating Point Stack.

Flash ROM Structure

Details the 512K Flash ROM composition, divided into 32 pages of 16K each.

System Routines

Explains accessing TI-83 Plus system routines using Z80 RST instruction and macro-instructions.

Variable Naming Conventions

Outlines rules for naming variables, including predefined and user-defined names and their formats.

System Variables Area

Describes preallocated system RAM variables essential for built-in functionality.

DRIVERS LAYER

Covers keyboard input, display access, and link port communication functionalities.

Display

Details accessing the TI-83 Plus display via system routines or directly writing to the display driver.

Graphing and Drawing — What’s the difference?

Differentiates between pixel-based drawing routines and graph routines tied to WINDOW settings.

TOOLS AND UTILITIES LAYER

Covers essential development tools like error handlers, utility routines, and debugging features.

Error Handlers

Explains setting up error exception handlers using AppOnErr and AppOffErr macros to capture system errors.

Temporary Variables

Discusses temporary variables used for intermediate results and their management.

Entering and Exiting an Application Properly

Details how applications interact with the TI-83 Plus application loader and state monitor.

Application Development Process

PROGRAMMING LAYER

Covers the final layer of TI-83 Plus architecture, focusing on TI BASIC, ASM, and Applications.

Applications

Defines applications as Flash ROM programs, their PC creation, signing requirements, and larger scale.

DEVELOPMENT SYSTEM

Introduces the simulator for general development, setup, and sample application creation.

Using the Simulator System — Requirements for Getting Started

Lists requirements for TI-83 Plus application development using Zilog Developer Studio and TI Simulator/Debugger.

Debugging the Application

Demonstrates setting breakpoints, modifying RAM, and using the Memory Map view for debugging.

Downloading the Application

Explains using TI GRAPH LINK or TI Connect to download applications to calculators.

Development Tools

DEVELOPMENT ARCHITECTURE

Outlines the TI development architecture based on the TI simulator/debugger and Zilog Developer Studio.

TI SOFTWARE SIMULATOR AND DEBUGGER

Describes the TI-83 Plus simulator for debugging applications, detailing menu options and operations.

Breakpoints

Explains setting and removing breakpoints via the manual setup dialog box in the debugger.

CPU View Window

Displays processor information such as index registers, stack pointer, and flags.

Flash View Window

Displays entire Flash memory contents, allowing address viewing and toggling between physical/logical modes.

RAM View Window

Displays entire RAM contents, allowing address viewing and toggling between physical/logical modes.

Key Press Recording and Playback

Allows recording and playing back key presses, with setup options for files and rates.

Support in Writing Applications

Lists resources for help in writing TI-83 Plus applications, including guides and tutorials.

Glossary

TI-83 Plus “Large” Character Fonts

TI83 Plus “Small” Character Fonts