Creating An Application For Debugging — One-Page And Multi-Page Apps; A Brief Overview Of Certificates And Application Signing; Creating Applications That Fit On One Page - Texas Instruments TI-83 Plus Manual

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Creating an Application for Debugging — One-Page
and Multi-Page Apps
In the section that discusses memory maps, you saw that there are up to ten 16K
Flash ROM pages available for storing applications. This storage area is also used for
archived calculator variables, so as the archive grows, fewer pages are actually
available for apps. In theory it is possible to create an app that takes up all 10 pages
and is 160K in size. However, most apps will surely be smaller and this is desirable to
conserve memory and download time.
Apps are always allocated in whole pages. It is not possible for an app to share a page
with another app or archived variables. If an app only uses 40 bytes it is still allocated
the whole 16K Flash ROM page. And if an app requires 16K+1 bytes, it is allocated
exactly two 16K Flash ROM pages. For this reason we say that apps are a 1-Page App
or a Multi-Page App. Creating multi-page is a little more complicated than 1-page apps,
so we will begin with 1-page apps.
A Brief Overview of Certificates and Application
Signing
In normal calculator usage, an application is installed in a calculator by downloading it
from a PC or another calculator via the link cable. When the app is received, it is
examined by the operating system loader for a valid digital signature. All Flash apps to
be distributed must be digitally signed before they will be accepted by the operating
system. Applications can be signed as freeware or authenticated applications.
Freeware applications can run on any TI-83 Plus or Silver Edition calculator. The
0104.key file and Wappsign utility are provided with the SDK and can be used to sign
applications as freeware. Authenticated applications require a certificate on the
calculator and must be signed by TI.

Creating Applications that Fit On One Page

Applications are written in Z80 Assembly language. While there are C to Z80 cross
compilers, TI recommends the use of assembly language for efficiency and memory
space reasons. The format of the source code depends on the assembler/linker
package that you use. With the package TI recommends (ZDS), App source code is
plain ASCII text. There is no special editor required. You can use any editor (such as
Notepad) that can save the file as plain ASCII. The required source code syntax also
varies by assembler. The examples and discussions provided by TI conform to the
requirements of the Zilog Developer Studio (ZDS) assembler and linker.
ZDS uses a file naming convention of *.asm for all source files containing executable
statements and *.inc for all include files.
TI-83 Plus Developer Guide
Chapter 3: Application Development Process
Third Release May 28, 2002