Texas Instruments TI-83-Plus User Manual

126 Chapter 3: Application Development Process
TI-83 Plus Developer Guide Third Release May 28, 2002
Branch Table Placement
Application execution begins at the address immediately following the header. The
branch table is not part of the header, but must be placed immediately after the header.
To resolve this conflict, a jump instruction to the start of the application needs to be
placed between the end of the header and the start of the table.
Also, the first entry in the branch table must be located at an address which is a multiple
of three bytes from the beginning of the page. You may need to add padding bytes
before the branch table to ensure this.
Branch Table Equate File
Whenever a branch table exists, an include file must also be generated that contains
equates for the branch table entries. Each equate in the file is the name of the routine in
the branch table with an underscore character prefixed to it. The associated value is the
byte offset where the routine’s table entry begins.
For example, the routine showGoodByeP2 exists on the second application page but
must be called from the first application page, so it needs an entry in the branch table.
The branch table entry for this routine happened to be located at a position 41 times
three-bytes from the start of the first application page.
; Byte offset 41 * 3
DW showGoodByeP2 ; Address
DB 1 ; Second app page
So in the include file the following equate is created.
_showGoodByeP2 equ 41*3
This include file must be included in any source code that calls or jumps to a routine on
another page.
Making Off-Page Calls and Jumps
When code calls or jumps to a routine on an application page different from the point of
the call, this is known as an off-page call or jump. The B_CALL and B_JUMP macros
must be used when making off-page calls and jumps. For example, when the routine
showHelloP2, which is on the second page, is called from the first page, the call must be
made as follow:
B_CALL showHelloP2
A call of the form
CALL showHelloP2
will not work at all.
When an on-page call, a call to a routine that exists on the same application page as the
point of the call, is made, the normal call opcode should be used. B_CALL and B_JUMP
should not be used in this case.

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