Texas Instruments TI-83-Plus User Manual

46 Chapter 2: TI-83 Plus Specific Information
TI-83 Plus Developer Guide Third Release May 28, 2002
 PagedGet
This routine has two functions. First is to fill the 16 byte cache
with mode data from the archive, whenever it has been
completely read. Second, is to return the next byte from the
cache to the caller. The first byte returned is at the location
input to SetupPagedPtr, followed by each consecutive byte
that follows.
Inputs:
Initial inputs are set by SetupPagedPtr, and are updated after
each subsequent call to PagedGet.
Outputs: ACC = byte read.
Cache pointers updated.
Cache reloaded with next 16 bytes of archive if exhausted.
Note: Both of these methods, direct and cached, will force an application to read data
from the archive sequentially. This can be very inefficient if the eightieth byte of an
archived equation needed to be read. An application would have to read through the
first 79 bytes one at a time.
In Ram, the solution would be to add 80 to the address of the start of the equation
and then do one read. In the archive, it is not as simple. An application has to be
wary of ROM page boundaries and offsets into a ROM page.
Applications can use the following code to add a two byte value to a ROM page
and offset archive address, so that page boundary crossing is adjusted for. This
routine will work for adding values up to 4000h (16K) maximum.
;
; Add DE to ROM page and offset: B, HL
;
BHL_Plus_DE:
ADD HL,DE ; add DE to the offset HL
BIT 7,H ; cross page boundary?
RET Z ; no, B, HL = ROM page and offset
;
INC B ; increase ROM page number
RES 7,H
SET 6,H ; adjust offset to be in 4000h
; to 7FFFh
RET
For example, look up archived AppVar MYAPPVAR, and read past its Symbol
Table entry in the archive to reach the data. Then read the two size bytes of the
AppVar.
Data
valid
Size of Symbol
entry + Data
Size varies by the name
size and data type
Size computed the same
as variables in RAM
Flag LSB MSB Symbol Table entry Variable Data Structure
Increasing addresses -------->
Table 2.12: Format of Archive Stored Variables

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