Dan's Home Page - TI-85 Calculators

TI-85 Calculators

Welcome to my TI-85 calculator and ZShell page. Here you can find links to some of the best sites about the calculator in general and ZShell in particular. ZShell is both an operating system and a shell for the TI-85 that allows one to run pure assembly code on the TI-85 calculator written for the z80 microprocessor. I have made a couple of games for Zshell, including Zelda 4 and PacMan-85. Be sure to check them out! Also, be sure to check out the new program for the PC, SpriteEdit , made by Chris Tossing and myself, that makes it easy to create your own sprites for assembly language games and applications on all the calculators!

www.TICalc.org is the number one site to visit to for information and programs related to the TI-85. From there, you can link to almost any web site dealing with TI-85 calculators that you can imagine. NOTE: This page is not entirely devoted to the TI-85, but the Texas Instruments calculators in general (TI-80, TI-81, TI-82, TI-83, TI-85, and the TI-92).
- The TI-85 section discusses the general aspects of the TI-85 graphing calculator; a good place to start for beginners.
- The Assembly section is the place to go for general information regarding assembly programming for the TI-85 or TI-92.
- Visit the Zshell page for information regarding ZShell, the operating system and shell for the TI-85. Expect to find plenty of information regarding the system in general and information about developing programs for it as well. This page will tell you all you need to know about developing software for ZShell.

ZShell is not the only shell on the market! Here's links and a brief description to two other award-winning shells!

CShell-NT is just a pumped up version of Zshell, including auto-powerdown from inside the shell and an instant contrast changer. More features are planned, such as a security lock.
Usgard is not your typical Z80 Shell. It includes powerful programming features such as relocation, library support, a Windows-95 type interface, improved built-in routines such as sprite routines, and VAT support. This is the shell for serious Z80 programmers, but not recommended for the average user because it is bulky and over-sized.

Do you feel like you need to be a rocket-scientist to be able to program in assembly? Well, with the introduction of this wonderful product, Higher Assembler Language (HAL), you don't have to be! This freeware program developed by two high school students, allows you to write your program in HAL-Basic, and it automatically converts the program into supper-fast assembly code. Included are multiplication, division, sprite, VAT, link-port, and a dozen more routines to ease your work. However, it is not recommended for advanced programmers because it is not very efficient, making programs 20-30% bigger.

ftp.TICalc.org is an excellent ftp archive of almost all the programs created for the TI-85 calculator, both in Basic and in Assembler.
Official Texas Instruments FTP Site contains plenty of TI-Basic programs for all occasions.

Frequently Asked Questions About TI Graphing Calculators
Hacking the TI-85 Calculator
TI-85 Tips, Tricks, Bugs, and Undocumented features
A Programmers Guide to TI-85 RAM
A Programmer's Guide to TI-85 ROM Calls
A Programmer's Guide to the TI-85 Ports
ZShell Function Library
The ZShell School is the best place for beginner programmers to get basic information on programming for ZShell. This site is specifically geared towards beginners.
TI-85 Assembler Programming is another excellent site geared towards beginners.
Accelerating the TI-85 deals with the plans for accelerating your TI-85 for up to three times. It involves opening the case, so if you are brave soul, click!

Well, that is about all you need to know to get started. I will not try to go into much detail here, for there are already a descent amount of excellent pages out there; there simply doesn't seem to be any need for one more. The rest of this page will focus and concentrate exclusively and enduringly on the elusive xStat system variable.

My Zshell Games

Zelda 4 is an action-packed, adventure role-playing game that is fun for all! You are the famous hero Link on a perilous journey through the Land of Dreams, meeting both friends and foes on a mission to save the beautiful princess Zelda from the Dark Lord of Dreams. But you must hurry, for the princess does not have much time. With your sword and magic skills at hand, you set out on your adventure, not sure if you'll ever see home again! This game was programmed by myself and Chris Tossing, with Patrick Jagoda designing most of the levels and enemies. (Source code available upon request.) Expect this wonderful trio to be back for more Zshell games in the near future!
Pac-Man is back, and this time for the TI-85 in the action-packed PacMan-85! This wonderful creation is a clone of the popular Nintendo game that came out in the '80s. You are a pac-man and your job is to eat all of the dots before the enemies get a chance to eat you! The more dots you eat, the more points you earn, and once you have eat all the dots, you advance to the next thrill-filled level. This game was imagined, designed, coded, supervised, tested, and approved for the mass public by none other than the great Dan Hussain himself. (Source code available upon request.)

xStat

Tips, Tricks, Bugs, and Undocumented Features

by Dan Hussain

Armand Tuzel

There are many surprises awaiting us when we play around with the xStat list variable. xStat by itself is a strange creature. For one, it is always in memory, taking 11 bytes of RAM. There is no way to get rid of it, as far I can tell. It just sits there quietly, timidly, waiting for you to uncover its fierce side! In the next few pages, I will attempt to document all of the weird things that happed when you screw around with this variable. Before we begin, however, I would like to make several things clear. Neither I nor Armand Tuzel are liable for any damage that this might cause to your calculator (after is unexpectedly hangs), to your math or physics grade (after all your programs are erased), to your self esteem (if nothing here works), or your family (after you smash the calculator on your little sister's head from frustration). It is highly recommended that you backup your calculator's memory before proceeding. Oh yeah, the work here has been compiled by my good friend Armand Tuzel and myself, spending many hours of work and patience. This work belongs to us, so please respect our rights.

General Information

To activate this bug, follow the following sequence of steps:

Reset all ([2ND] [MEM] [RESET] [ALL] [YES])
If necessary, turn up contrast.
[2ND] [SOLVER]
[ALPHA] [(-)] [ENTER]
[2ND] [CATALOG]
[CUSTM] [CUSTM]
[EXIT]
[2ND] [LIST]
[EDIT]
xStat [ENTER]

You should now see three zeros followed by some other nasty characters. What you are looking at is a RAM dump.

Explanation

In this section, I will try to explain what has just happened. When you put a space into the solver menu, you cross link the 3rd custom menu spot with the xStat variable. When you put something into the 3rd custom menu spot, you do a RAM dump into the xStat variable. Now, when you play around with the first value of this list, weird things happen to your custom menu.