TI-99/4A FAQ: Text Adventure Games

Adventure cartridge – Scott Adams adventures

https://www.mocagh.org/loadpage.php?getcompany=ai&npp=25&whatsnew=0&start=0&series=TI-99%2F4A+Adventures+Series  has a nice list of the games available for this cartridge. You need a cassette player/cable or disk system to load the games with the adventure module. No other expansion is required it works fine on stock console.

Adventure Games:

Others listed: https://intfiction.org/t/list-of-games-in-scott-adams-ti-99-4a-format/49771

Return to Pirate’s Isle

This game is unique as it was only created for the TI-99/4A (officially adventure #14) and it is the first graphical adventure game published for home computers.


Infocom officially released the following games for the TI-99/4A

  • Zork I
  • Zork II
  • Zork III
  • Enchanter
  • Sorceror
  • Deadline
  • Witness
  • Starcross
  • Suspended
  • Planetfall
  • Hitchiker’s Guide to the Galaxy
  • Infidel
  • Cutthroats
  • Sampler

The TI community has released an updated interpreter that supports all of the original games plus additional

  • Ballyhoo
  • Suspect
  • Leather Goddesses of Phobos*
  • Spellbreaker
  • Seastalker

A recent infocom compatible release was made that includes a TI-99/4A release

Hybernated – 1 https://atariage.com/forums/topic/321529-for-fans-of-old-infocom-games-something-new/

TI-99/4A FAQ: Abbreviations

By Dan H. Eicher
    AVPC - Advanced Video Display Processor, produced by Digit Systems
            (Tom Spilane) - This PBOX card use an 9938. 
    c - Small C by Clint Pulley for the 99/4a.
    E/A - Editor Assembler.
    FDC  - Floppy Disk Controller. 
    FWEB - Funnel Web.
    GRAMULATOR - Graphics Ram Module produced by Cadd Electronics
                 allows the user to load/modify and run cartridges.
                 Unlike the GramKracker produced by Millers Graphics
                 with modifications, this unit could also run MBX
    GRAM KRACKER - See Gramulator.

    Grand Ram - A ramdisk produced by DataBiotics. Unique in that 
           it both battery backed up like a Horizon Ramdisk and 
           provided print spooler software (like the Myarc 512K)
           card. It also included connectors on board to connect
           to emulate the PBOX bus and cartridge port.
    GROM - Graphic ROM  
           Rom Memory developed by TI that automatically increments.
    HFDC - Myarc Hard Floppy Disk Controller.
    MBP - Eight port analog to digital card with real time clock.
    MBX - Milton Bradley Expansion Unit (yes the toy maker) allowed 
          the 99/4a to use voice directed games.
    PBOX - Peripheral Expansion Box also known as PEB.

    PC99 - A software package for MSDOS PC's (486-50 or faster) that
           emulate a TI99/4A. This is commercial software and well 
    PGRAM - Like the GramKracker, but on a PBOX card. 
    PIO - Parrallel/Printer Port.
    POP-CART - Cartridge produced by OPA that up to 512K of grom
               code and any number of cartridges could be placed.

    SOB - Son Of a Board. This board also plugs into the console,
          in the GROM1 socket. It adds an enhanced menu upon power
          up and fixes some video initialization problems that are
          transparent, unless you are using a 9938 or 9958 video 
          controller chip in your system. 
    TIM - TI Image Maker. This is a an 80-column board produced by 
          OPA. It had a Yamaha 9958 chip and came bundled with the
          SOB. It mounts inside the TI console in the TMS9918 socket.

    V9t9 - A software package for MSDOS PC's (386-25 or faster) that
           emulates a TI99/4A. This is freeware (produced by Ed. 
           Swartz) and no support from the author is available,
           but the source code is.
    XB  - Extended Basic.

TI-99/4A FAQ: Sidecar expansions

Many Sidecar Expansions were made for the TI-99/4A:

TI Sidecars:

  • Speech Synthesizer
  • 32k Memory Expansion
  • SS/SD Disk controller
  • RS232
  • PCode
  • Video Controller
  • Solid State Thermal Printer

Corcomp Sidecars:

  • CC9900 Micro Expansion System
    • The 9900 Micro expansion from Corcomp provided 32k and also an optional board can be installed to provide a DSDD disk controller and RS232/PIO ports
    • Power Supply  5 pin DIN
  • Corcomp Clock
  • Corcomp 256/512k Ramdisk

Myarc Sidecars


Other Sidecars

  • Boxcar Peripherals RS232
  • Axiom ParallAx Printer Interface
  • Triton Turbo XT

Homebrew Sidecars

  • JediMatt42
    • 32k RAM Sidecar
      • https://jedimatt42.com/ti32kmem.html
    • TIPI Sidecar (ram card with 44pin required)
      • https://github.com/jedimatt42/tipi/
  • Arcadeshopper
    • SAMS 1mb Sidecar
  • Jgparker
    • 32k/TIPI combo card
      • fits in original speech synth case (after removing original board) also 3d printed cases are available
      • https://github.com/jgparker/tipi

TI-99/4A FAQ: Power Supplies

External Power Supplies:

  • TI-99/4A USA: 

Internal Power Supplies:

Power supply from a 99/4 (NOTE: NOT COMPATIBLE WITH 4/A)

Power supply from a 99/4A

Power supply from a 99/4A QI


This is the connector on the back of the console that the ac adapter plugs into. Some of these connectors have 4 pins, while others have 3. The newer power supplies (QI) only have 2 pins. They way they were set up you can use any ac adapter with any of the consoles.

The AC voltages in are:

1. Black 8 volt

2. White 16 volt

3. Red 5 volt

4. No connection

The power supply is a very standard setup, and could be replaced by any standard PC power supply.

The DC voltages out are:

Pin 1 = -5 volt

Pin 2 = +12 volt

Pin 3 = GND

Pin 4 = +5 volt.

No AC Voltage? check the fuse!

TI was required by the UL to add a fuse to the external power supply. Their solution? add a pigtail to the power cord with the fuse in a little plastic box.

These fuses tend to blow after so many years of use, so the fuse needs to be replaced or just remove the pigtail if you are using a power strip with built in circuit breaker making the fuse unnecessary.  You will find it’s just stuck on the old plug with some adhesive and it should come apart with some effort.

Fuse type:  4/10A 250V 


Schematic for power supply (not QI)

Here is an interesting project replacing the console power supplies with a new board:


TI-99/4A FAQ: Extended Basic

Extended Basic Module from Texas Instruments

  • The Extended Basic module was not included with the console and was semi-expensive originally. 
  • Extended Basic exists in two distinct versions, Version 100 and Version 110. To determine which you have us this small program:
      • 10 CALL VERSION(A) :: PRINT A
    • Only a very small handful of the earlier Vn 100 were sold. 
    • Principal difference is speed: Version 110 is much faster.
    • Version 110 fixes bugs and supports sprites and features on the 4A that were not available on the 99/4
    • EXTENDED BASIC is a much larger language than TI Basic.
    • The increase in operation speed is not shown by magazine ‘bench tests’ which use very short specific programs. In a typical program you will find the program runs in about 30% less time. Line transfers and screen handling are particularly faster than in TI Basic. This is due to the fact that some of these routines are in assembly language in Extended Basic while TI BASIC is 100% GPL. 
    • Extended Basic also adds any new commands and functions over TI BASIC enabling better use to be made of limited memory, and also permitting friendlier programs to be written.  
    • Extended Basic allows for multiple commands per program line using  :: as a command delimiter
    • Extended Basic supports the 32k memory expansion allowing 24k to be used for program data, the rest of the memory is used for stack.
    • Many TI BASIC programs can be loaded in Extended Basic, and will then run faster.
      • Exceptions are:
        • TI Basic programs over 12k cannot be loaded due to lack of memory. (memory expansion doesn’t help with this due to TI BASIC programs load into VDP ram only)
        • Some TI Basic programs will load but cannot RUN due to lack of memory.
        • TI Basic has two extra character sets: if these are used, they will produce a BAD VALUE error in Extended Basic. Extended Basic uses the memory saved by dropping these sets (15 and 16) to produce the Sprites
        • Extended Basic manual: https://www.digitpress.com/library/manuals/ti994a/ti%20extended%20basic.pdf

Versions and variations on Extended Basic:




TI-99/4A FAQ: Terminal Programs

The most feature rich terminal program for the 4/a is TELCO.. This supports ANSI graphics (NO COLOR) and 40 and 80 column modes (80 column requires a 9938 or greater VDP and does not work currently with F18a 80 column mode) Multiple file transfer protocols, printer spooling etc..

This file contains a disk image, pdf format manual and keyboard overlay http://ftp.whtech.com/communications/Telco%20-%20Complete%20Package.zip

Other terminal programs and their features

Term80 – 80 column terminal on stock VDP, uses a TINY FONT but supports color ANSI and high baudrates using specialized rs232 routines and memory devices for buffering data..  buggy and incomplete but still pretty cool

MXT – Mass Transfer – allows for multiple file transfers and standard ascii terminal emulation , xmodem included as well this has also been ported to work as a telnet client for TIPI

Fast Term – ASCII terminal program that works up to about 19200 baud..

Terminal Emulator and Terminal Emulator II – cartridge based terminals support 110 and 300 baud, 7 bits even parity and has a proprietary terminal emulation mode allowing for graphics and sound,  also only supports file transfers from TE compatible systems (TIBBS FOR INSTANCE)

TI-99/4A FAQ: BBS’s


  • 9640 News BBS  (currently offline)
    • URL: 9640news.ddns.net
    • PORT:9640/9918?
    • SOFTWARE:Mystic
    • PLATFORM: ??
  •  Heatwave BBS
    • URL:heatwave.ddns.net
    • PORT:9640
    • PLATFORM: Geneve
  • My TBox (german)
    • URL: MyTBox99.ddns.net
    • PORT:61643
    • SOFTWARE: After Hours BBS
    • PLATFORM: TI-99/4A
  • The KEEP BBS
    • PHONE: 503 852-3170
    • URL: thekeep.net
    • PORT:23
    • SOFTWARE:Worldgroup
    • NOTES: multi-user chat, gaming, many file areas for retro machines, dialout to other BBS”s using my modem with /GO DIALOUT on the BBS
  • The KEEP BBS After Hours
    • URL:thekeep.net
    • PORT:9918
    • SOFTWARE: After Hours BBS
    • PLATFORM: TI-99/4a
  • The Hidden Reef
    • PHONE: 718 448-9402
    • PLATFORM: TI-99/4A
  • FuSiON BBS
    • URL: fusionbbs.ddns.net
    • PORT:9640
    • SOFTWARE:Mystic
    • PLATFORM: Raspberry PI

TI-99/4A FAQ: Development Resources

mirror of https://atariage.com/forums/topic/153704-ti-994a-development-resources/

Don’t forget to visit Ninerpedia; our wiki about the TI-99/4A. Check here.


If you are the owner of one of the programs or sites and do not want it posted, please let me know and it will be removed immediately.

Also if you think a reference to an important development resource is missing, then please let me know and I’ll be happy to add to the list.


If you are new to the TI-99/4A or returning after a long time, then you might want to check out the TI-FAQ page here.

Also make sure to visit the TI-99/4A Home Computer Book Archive by @airernie, now hosted by @acadiel.

It’s a great collection of excellent technical books about programming the TI-99/4A.


Latest update: May 5th 2019



1. Emulators



classic99 win

Windows-based emulator including TI-99 ROMs under license from Texas Instruments.

Debugger, memory heatmap, OS file support, support for 128K bank-switch carts, can create ROM/GROM cartridges, possibility to record AVI movies.

User manual is included.

Check the classic99 Updates thead for the latest news on classic99.

Click here to watch Tursi’s classic99 tips and tricks video tutorial.

(Author: @Tursi)


MAME win+linux

Multiple system emulator that supports the TI-99/4, TI-99/4A, TI-99/8, and Geneve.

Emulates more than 400 systems. Requires ROMs from the original systems.

Features a powerful Debugger, most accurate emulation, support for 64K bank-switch carts / Gram Kracker / UCSD p-code expansion card.

Possibility to record AVI movies.

Also see the MAME section in ninerpedia.

(Author: @mizapf)


Js99’er All major browsers

TI-99/4A emulator written in javascript. Has support for TMS9918A VDP & supports most of the F18A functionality, TMS9919 sound.

Virtual disk drives using google drive.

Some preloaded games, demos and applications included.

Js99’er development thread on Atariage can be found here.

Js99’er source code repository on Github can be found here.

(Author: @Asmusr)


V9t9 win+linux

TI-99/4A emulator written in java. Has support for TMS9918A VDP, TMS9919 sound & TMS5220 speech.

Debugger included. V9t9 also supports the UCSD P-Code system.

Some of the advanced V9t9 features include: ability to save/restore emulator state, record & playback, support for V9938 VDP.

Requires ROMs from the original systems.

This emulator needs the Java Runtime Environment available for free at Oracle.

V9t9 discussion thread can be found here.

(Author: @eswartz)


Win994a win

Windows-based emulator of the TI-99/4a

Good TMS9900 cross-assembler included. No debugger.


Ti994w win

Windows based emulator. Offers 80 column support, SAMS card 1Mb of RAM, V9938 support, built-in debugger, …

(Author: @F.G. Kaal)


TI-99/Sim linux

Linux-based software simulation of the TI-99/4A.



Commercial DOS-based emulator licensed by Texas Instruments to sell ROMs.

2. Programming languages



Assembly language – Software

Winasm99 win

Windows based TMS9900 cross assembler with GUI and ability to build 8K cartridge roms.

Is part of the Win994a emulator.


asm990 linux

Linux based cross Assembler for the TI 990 by Dave Pitts.

You’ll also need lnk990 a separate linker which can be found on the same page.


TIasm win

TMS9900 cross assembler TIasm will build 8K console (>0000) or cartridge (>6000) rom.

Is part of the old V9T9 emulator package. Source is included.


Editor/Assembler IV TI-99/4A

Editor/Assembler IV is a module for the TI99/4A home computer. The software this cartridge contains is the in TMS9900 assembler rewritten Editor and Assembler loader, Program loader and an implementation of

my own written Linking Loader and a simple debugger. The editor and debugger are running completely in the module space (>6000 – >7FFF). The assembler is copied from EPROM to CPU RAM before it is started.

(Author: @F.G. Kaal)


XA99 – Cross Assembler 99 win

XA99 (Cross Assembler 99) is a program for assembling TMS9900 assembler code on the PC.

(Author: @F.G. Kaal)


L99 – Linker 99 win

L99 is a tagged object file linker by Fred Kaal for creating program files for the TI99 and Geneve home computer.

(Author: @F.G. Kaal)


xdt99 – TI 99 Cross-Development Tools win, linux, OS X

The TI 99 Cross-Development Tools (xdt99) are a small suite of programs that facilitate the development of programs for the TI 99 family of home computers on modern computer systems.

All programs are written in Python and thus run on any platform that Python supports, including Linux, Windows, and Mac OS X.

Includes xas99 (TMS9900 cross-assembler), xga99 (GPL cross-assembler!) and some command line tools for handling disk images and nanoPEB/CF7A+ volumes.

The development thread on atariage can be found here.

(Author: @ralphb)


Assembly language – Manuals



Editor/Assembler reference manual PDF

The official Editor/Assembler reference manual. Note that this is not a tutorial for beginners.

Still, it’s an essential manual when writing assembler for the TI-99/4A.

The online version can be found here.


COMPUTE!’s beginner’s guide to assembly language on the TI-99/4A PDF

The Lottrup book. The only manual available today focusing on programming games in TMS9900 assembler.

The examples in the book are for the Mini Memory line-by-line assembler which is rather limited.

The manual also contains a few errors. Check here for the corrections.

Nonetheless this book is a must-read for everyone seriously interested in writing assembler games for the TI-99/4A.

The online version can be found here.


Introduction to Assembly Language for the TI Home Computer PDF

The Molesworth assembly language introduction book.

Covers VDP communication, keyboard reading, file access and a lot more.


The Art of Assembly series PDF

The full series of articles by the late Bruce Harrison compiled as PDF. Over 600 pages, very well written and thorough.


Assembly on the 99/4A WEB

Excellent thread on Assembly language programming for the TI-99/4A, focussing on game loops, etc.

(Author: @matthew180)



Library for programming games in TMS9900 assembly language.

Has routines for handling tiles, sprites, sound & task scheduler.

Documentation manual PDF is included.

(Author: @retroclouds)



BASIC – Software

Power BASIC TI-99/4A

This is a port of the ‘Power BASIC’ interpreter used with the TMS9995-based Powertran Cortex machine.

It is written in pure assembly. Graphic commands, sprites and saving to disk are supported. Currently no sound and speech supported.

Power BASIC instruction manual available.


Playground TI-99/4A

Playground is a package making it possible to create assembly language programs that run from TI BASIC on an unexpanded console using only a cassette player to load the program(!)

Although primarily intended for use in TI BASIC, programs written for playground can be run from XB, saved in E/A 5 format, loaded into a supercart, and even made into an actual cartridge.

The manual describes in detail the differences in style necessary when programming for an environment that runs in only 256 bytes of memory.

There is a library of subroutines for printing text, printing a number, shifting blocks in VDP, generating random numbers, using the line editor from BASIC, HCHAR, VCHAR,GPLLNK, a bit reversal routine, and a fast scroll routine.

Source code is included for three different programs that should help you get started.

Check here for the development thread on Atariage.

Check this related thread for some clever work based on Playground.

(Author: @senior_falcon)



Extended BASIC – Software

Extended Basic Game Developers Package “ISABELLA” TI-99/4A

This package has been extensively updated to be faster, more versatile, and much simpler to use.

It consists of two applications that make it possible to produce arcade quality games with XB.

Although they are designed to complement each other, each is a stand alone utility.


This is meant to be used with the Classic99 emulator, but the resulting programs are fully compatible with a real TI99 with nothing more than XB, 32K and a disk drive.


Note that the included XBGDP package has an option to use the older TI BASIC only runtime routines if desired.

It replaces for the older “Harry Wilhelm’s BASIC COMPILER” and as a bonus, it’s much easier and faster to use.

(Author: @senior_falcon)


1) XB256

XB256 lets you toggle between two independent screens as desired. Screen2 lets you define all 256 characters and have up to 28 double sized sprites using the character definitions available to Screen1. Scrolling routines let you scroll characters left, right, up, or down or scroll using single pixels.

There is a text crawl that gives an effect similar to the STAR WARS title screen. You can highlight text, set the sprite early clock, print in any direction on the screen using 32 columns, read/write to VDP ram, write compressed strings or sound tables to VDP ram, play a sound list, and catalog a disk.


A utility lets you save selected areas of VDP memory as compressed strings that cn be merged with your program. With this, character definitions, sound tables, screen images, etc. can be saved in a more compact form that can be loaded virtually instantaneously, even in XB

There are two utilities that convert the CALL SOUNDs in an XB program into a sound table containing music and sound effects. Sound tables can be loaded directly into VDP memory and played automatically while your XB program does other things. Also, a second player can play a different sound list simultaneously with the first, so you can have backgroundmusic playing and add sound effects on top of the background music.



COMPILER lets you compile an XB program into an equivalent assembly language program that will run about 30 times faster. All the XB256 subprograms are supported by the compiler and in general, all the major features of XB are supported, including XB style IF/THEN/ELSE and named subprograms. About the only XB features that are not supported are DEF and the trig functions.


T80XB TI-99/4A

T80XB is a collection of assembly language subroutines that give the Extended BASIC programmer easy access to the 80 column screen mode offered by the F18A and other 80 column upgrades.

Lets you select from two independent screens. G32 is the default screen when a program starts running.. This is the 32 column graphics mode screen normally used by Extended BASIC. It is accessed using the usual XB graphics statements. T80 is the 80 column text screen which offers 24 rows of 80 columns.. You can toggle between the two screens as desired, preserving the graphics on each screen. When using the T80 screen there are assembly equivalents that replace PRINT, CLEAR, COLOR, INPUT, CHAR, HCHAR, VCHAR plus routines that will scroll the screen and invert text on the screen.

(Author: @senior_falcon)


RXB 2015E TI-99/4A

RXB 2015E is an updated version of TI Extended Basic.

Most bugs in XB have been fixed in RXB and GKXB is in the main core of RXB.

RXB has features no other XB has such as Batch processing or Hard Drive Access or updated CALL routines.


The below RXB tutorials on Youtube give a good overview of RXB’s power:

RXB DEMO 1 video

RXB DEMO 2 video

RXB DEMO 3 video

RXB DEMO 4 video

RXB DEMO 5 video

RXB DEMO 6 video

RXB DEMO 7 video

RXB DEMO 8 video

RXB DEMO 9 video

RXB DEMO A video

RXB DEMO B video

RXB DEMO C video


Full documentation, examples and GPL source code included in the ZIP package. Cartridge image for classic99 emulator also included.

Requires a GRAM device such as a GRAM Kracker for running RXB on the TI-99/4A.

(Author: @RXB)


My Little Compiler (MLC) TI-99/4A

Library for using assembler-like language & routines from Extended Basic.

Great for putting more power in Extended Basic programs. Now includes a precompiler for high-level language syntax. Demo Pong game and documentation included.

The MLC development thread can be found here.

Check out the video by @rocky007 on his MLC based TI-99/4A port of Kaboom!

(Author: @moulinaie)


The Missing Link 2.0 (TML) TI-99/4A

The zip archive contains “The Missing Link 2.0” and its documentation. This was published by Texaments in 1990.

It gives the XB programmer easy access to the bit mapped features of the 9918 VDP.

Full color cartesian graphics, turtle graphics, sprite graphics (32 sprites with auto motion) are supported.

Text can be displayed on screen with fonts having sizes ranging from 4×6 pixels to 8×8 pixels.

The manual is updated with many previously undocumented features. A tutorial called “Potatohead” is included.

There is a loader that embeds A/L programs in high memory – they can be saved as an XB program and run directly out of high memory.

(Author: @senior_falcon)


TidBiT – BASIC/XB Translator win, linux, OS X

A translator program that reads a program written in a custom, structured form of BASIC and translates it to a BASIC / Extended BASIC program.

PHP required when doing a local installation.

Check here for the latest revision, installation instructions included.

(Author: @matthew180)


Kull KXBII Extensions TI-99/4A

Kull Extended BASIC II programming package. High resolution graphics and clock support in Extended Basic. Documentation by @hloberg.



Extended BASIC – Manuals



COMPUTE!’s Programmer’s Reference Guide to the TI-99/4A PDF

TI-Basic programming manual touching graphics and sound.


COMPUTE!’s TI Collection volume One PDF

The online version can be found here.

Best of TI-Basic programming by C. Regena


Texas Instruments TI-99/4A user reference guide PDF

The official user reference guide with details how to setup and connect your TI-99/4A.

Includes an introduction on the TI-BASIC programming language.


Extended Basic reference manual PDF

The official extended basic manual, explaining the 40 new or expanded commands, sprites, etc.

Check here for the online version with command lookup functionality.


MG Night Mission PDF

Advanced tutorial on how to program an arcade game in Extended Basic.


MG Smart Programming Guide for Sprites PDF

Advanced tutorial on how to efficiently use sprites in Extended Basic.


C – Software

C99 v4 TI-99/4A

C99 is a small C compiler for the TI-99/4A written by the famous C. Pulley. Documentation included.


C99C – C99 cross compiler and optimizers win

C99C is the enhanced PC version of the C99 compiler for the TI99/4A home computer.

Also included are multiple optimizers for compacting the generated assembly source (C Optimizer, Function Call Optimizer, …)

(Author: @F.G. Kaal)


GNU C Compiler (GCC) win + linux + osx

GCC for the TMS9900 allows you to cross-compile C programs on your PC (Linux, OSX or Windows) for the TI.

Insomnia’s release contains a set of patches against GCC 4.4. Just check out the code from the GCC project, apply the patches and build according to the build instructions

for your platform and you’re on your way to write programs and games for the TI in a high level language that rival the speed of assembly. And if you need just that little

bit extra in terms of speed, you can always inline TMS9900 assembly for the critical sections of your code and compile everything with the same toolchain.

For access to the VDP, the SN76489, etc… you can use Tursi’s ti99 library, which you can find in the GCC thread.

Hop over to the INSOMNIA LABS blog for background information on this port.

Check the “Setting up the GCC compiler for the TI-99/4A video by @Tursi for detailed steps on how to build and install GCC on your Windows PC.

You can now download the cygwin binary port of the older TI GCC 1.10 for Windows here. (Thanks @lucien2).

(Author: @insomnia)



Fortran – Software

99-9640 Fortran TI-99/4A & Geneve

The zip archive contains LGMA Products’ FORTRAN v4.4 in both a version for the TI-99/4A and the Geneve 9640 computer.

Documentation in PDF format included. The discussion thread on Atariage can be found here.

Special thanks to: dano




Forth – Software

Turboforth TI-99/4A

A brand new implementation of the Forth langugage for the TI-99/4A.

The Forth system itself is written in assembler and is optimized for speed.

It runs from the cartridge space so there’s plenty of space for your program in the 32K memory expansion.

Check TurboForth.net the companion web site for the TurboForth system.

Click here for seeing some Turboforth video tutorials.

(Author: @Willsy)


TI Forth Instruction Manual “2nd Edition 2013” PDF

2012 enhanced version of the original TI Forth Instruction Manual in PDF format by @Lee Stewart.

Look here for details on manual improvements, etc.

The updated TI-Forth system disk can be found here.

(Author: @Lee Stewart)



fbForth TI Forth with File-based Block I/O zip

fbForth uses Level 3 file I/O for I/O of Forth blocks. It also implements 80-column text mode if you have a system with that facility.

fbForth 32KB 2.0.X ROM cartridge available.

(Author: @Lee Stewart)



CAMEL99 V2 Forth TI-99/4A

Multi-tasking Forth for the TI-99/4a. CAMEL99 Forth has been built as an educational tool for those who are interested in how you could cross-compile Forth to a different CPU using an existing Forth system.

Camel99 Forth Development thread on Atariage can be found here.

(Author: @TheBF)


GPL – Manuals/Tutorials

GPL Programmers Guide PDF

The original GPL programming reference manual from Texas Instruments.

Covers all opcodes and advanced stuff like coincidence detection, I/O routines, etc.




GPL HOW 2 Series video

A complete series on how to program GPL (Graphics Progroamming Language) on the TI-99/4A.

Each tutorial has its own support package with example code, GPL assembler, etc.

Video tutorials done by Rich, the programmer of Rich Extended Basic.

(Author: @RXB)


GPLHOW2A – Introduction video / zip

GPLHOW2B – Sprite demo video / zip

GPLHOW2C – How to make a Screen Editor like TI Writer or Editor Assembler video / zip

GPLHOW2D – Editor Assembler TI BASIC support.video / zip

GPLHOW2E – DMII cartridge upgrades and how GPL works video / zip

GPLHOW2F – TI Basic to GPL. Converting a TI Basic program to GPL video / zip

GPLHOW2G – TI Basic CALL SOUND to GPL video / zip

GPLHOW2H – Simultaneous sound lists and interrupt timer in GPL video / zip

GPLHOW2I – XB2GPL demo of a XB game Baloons converted into a GPL program video / zip

GPLHOW2J – Update to GPLHOW2I and adds a automatic music to the game from the last demo video / zip

GPLHOW2K – How to make XB Program Image files into I/V 254 files video / zip


TI-Intern PDF

Details on “Monitor”, the OS of the TI-99/4A. Disassembly of console ROM/GROMS and GPL interpreter.

Has details on interrupt routine, utility subprograms, basic interpreter, etc.


The thread “The TI-99/4A Operating System” is an ongoing community project for commenting the source code of the TI-99/4A ROM and allowing it to be assembled with todays’ assemblers.



LOGO – Manuals

TI-LOGO programming manual PDF

The official TI-LOGO programming manual.

The online version can be found here.



Pascal – Software

Turbo Pasc’99 TI-99/4A

The zip archive has the patched version of Wiposofts Turbo Pasc’99 which you can run on your favorite emulator or on the TI-99/4A itself.

While Turbo Pasc’99 is not as complete an implementation of Pascal as the UCSD Pascal system, it does have the advantage of not requiring

any special hardware other than 32K RAM and a disk drive, and will likely meet the programming needs of most TIers.

Check here for an english translation of the german documentation.

This version is started by running the Editor Assembler #EA5 program image DSK1.TP99A

Special thanks to: @Vorticon, @apersson850, @retroclouds and @lucien2


Pascal – Manuals


The official UCSD Pascal programming manuals and disks. The zip file (70 megabytes) contains all manuals in PDF format.

Here are the PDF manuals for online viewing: Compiler, Editor, Filer, Utilities, Assembler, Linker, p-code card

The UCSD system disk images in v9t9/MESS format can be found here.

Note that you need the UCSD P-code expansion card for running UCSD Pascal on the TI-99/4A.


Thierry Nouspikel has lots of information on the technical implementation of UCSD Pascal on the TI-99/4A.

Check here for details on the P-Code card and here for details on the P-Code system software.

Also a lot of details on UCSD Pascal in general (p-system vm, documentation, cross compiler, …) can be found here.


3. Technical Documentation






TMS9900 Microprocessor Data Manual PDF

Data Manual on the TMS9900 16-bit processor. The TMS9900 is the CPU used in the Texas Instruments TI-99/4A Home Computer.

Contains instruction execution times, opcode size, etc.


TMS9901 Programmable Systems Interface Data Manual PDF

Data Manual for the TMS9901, Interrupt and I/O interface controller


VDP Programmer’s guide PDF

The official programmer’a guide for the TMS9918A and its variants. The 9918A is the Video Display Processor

chip used in the TI-99/4A and several other home computers + game consoles of that era.


SN76489 sound chip datasheet PDF

Data sheet for the SN76489 sound generator. The TMS9919 in the TI-99/4A is close to being identical with the SN76489.


TMS5220 Speech Synthesizer Data manual PDF

Data manual for the TMS5220 chip used in the TI-99/4A speech synthesizer device.


Interface standard & Design Guide for TI 99/4A peripherals PDF

The purpose of this manual was to consolidate all information available in the public domain on the design and development of peripherals for the TI 99/4A computer into one reference. Also covers the software aspects such as DSR architecture, PABs, etc.


ROM Command Module Guide 2.0 PDF

This manual provides a complete description of how Assembly Language User Programs need to be written so that the object code can be downloaded into (EP)ROM’s which canthen be used in the “(EP)ROM module”, a module designed to be used with the TI 99/4A Home Computer.


TI Hardware Manual txt

Compilation of valuable hardware & programming info on Myarc memory cards, Disk Controllers, Hard Drives, CPU identification (TMS9900, TMS9995, TMS99000) in assembly language, etc.


DSR (Device Service Routine) / Disk & File Management

Device Service Routine Specification for the TI-99/4(A) Personal Computer PDF

Functional Specification for the 99/4 Disk Peripheral PDF

Software Specification for the 99/4 Disk Peripheral PDF

GPL Interface Specification for the 99/4 Disk Peripheral PDF

File Management Specification for the TI-99/4 Home Computer PDF

File Operations in assembly language


4. Homebrew Hardware



Graphics & Sound

F18A Video Display Processor

The F18A is a FPGA based hardware and pin compatible replacement for the TMS9918A/TMS9928/TMS9929 VDP’s (Video Display Processor).

Besides VGA output it offers enhanced functionalities such as 80-column mode, additional video resolutions, hardware register scrolling, an embedded TMS9900 compatible GPU, etc.

The development thread on Atariage, which includes the F18A programming documentation can be found here.

The store on code|hack|create has the details on F18A availability, costs, etc.

(Author: @matthew180)


SID Master 99 sound synthesizer card

The SID Master 99 is a new sound synthesizer expansion card for the Peripheral Expansion Box.

It integrates the famous MOS 6581 or 8580 SID chip (as used in the Commodore 64 home computer).

SIDPLAY99 sound player software available for use with this expansion card.

The store on DSAPC has the details on Sid Master 99 availability, costs, etc.

(Author: @marc.hull)


Homebrew cartridge boards

There are a number of Homebrew cartridge boards available to the users of the TI-99/4A now.

Each has its own advantages and disadvantages from a usability standpoint, and some earlier types are only available by having your own made.


To read the PCB layout files mentioned below, you need the ExpressPCB software which is available for free. Check here.

The files are currently not released in Gerber/Excellon format, but can be converted to it using the RobotRoom Copper Connection software, available here.

Note that to convert files to Gerber format you have to have the licensed version of the software ($50).


16K board PCB file

The first of the new cartridge boards is the 16K board designed by @acadiel and @Stuart.

This board used an inverted output from a 74LS379 to select between two 8K banks at >6000 in the TI memory map.

The banks are selected by writing to >6000. This board allows most of the third-party cartridges designed for the 99/4A to be replicated.

Further details on this board (components, EPROMS, software, etc.) can be found in: 16k_board_details.rtf


FlashROM 99 PCB file, firmware source code

The TI 99/4A Flash ROM Cartridge, or FlashROM 99 for short, is a cartridge for the TI 99/4A home computer that allows for running ROM cartridge images stored on an SD card.

The FlashROM 99 supports ROM-only images of up to 32K that use the write-to->60xx bank switching scheme. It will not work with programs using GROMs or CRU-based bank switching.

The cartridge does not require the Peripheral Expansion Box and runs on both PAL and NTSC consoles.

Discussion thread on Atariage can be found here.

(Author: @ralphb)




FinalGROM99 PCB file, firmware source code

The TI 99/4A FinalGROM Cartridge, or FinalGROM 99 for short, is a cartridge for the TI 99/4A home computer that allows you to run ROM and GROM cartridge images from an SD card.

It succeeds the FlashROM 99 released in 2016.


The FinalGROM 99 supports ROM images, GROM images, and mixed images of up to 1 MB in size that use the write-to-ROM bank switching scheme.

The cartridge does not require the Peripheral Expansion Box and runs on both PAL and NTSC consoles, including modified consoles with an F18A.

It will also run on v2.2 consoles and enables those to run ROM-only programs.


The development thread on Atariage can be found here.

(Author: @ralphb)




5. Utilities (file transfer, graphics, sound, …)



File Transfer

TIImageTool win + linux

TIImageTool is a tool that allows you to open disk image files as used with many emulators, and to work on them with common disk operations (like cut/copy/paste of files).

It is particularly tailored for use with MESS but can also be used with other emulators.

Has support for v9t9 format, PC99 format, CHD format, working with files & directories, Archiver support (can process Archiver files on the images), …

This utility needs the Java Runtime Environment available for free at Oracle.

Supports Cf7a+ card images.

(Author: @mizapf)


TI99Dir win

TI99 filemanager for windows. Great for transferring disk images to the TI-99/4A.

Supports Cf7a+ cards and Cf7a+ card images.

(Author: @F.G. Kaal)


TiDisk-Manager OS X

The TiDisk-Manager is a disk tool for disk images from floppy disks used by a TI-99/4A home computer.

You will need an Apple Macintosh or Hackintosh running with Mac OS X 10.9 or newer.

Has many features including file preview, export, etc. and even an interactive editor to disassemble program files and create good readable source code.

The development thread on atariage can be found here

(Author: @HackMac)


Cf2k – Compact Flash 2000 TI-99/4A

Cf2k (Compact Flash 2000) is a file manager for the TI99/4a with a CF7A+ compact flash adapter.

With CF2k it is possible to protect/unprotect files, rename files/volumes, format volume, mount volume, copy/move/delete files,

execute program files, …

Supports Cf7a+ cards.

(Author: @F.G. Kaal)



Convert9918 win

Windows program for converting images into TMS9918A Graphics II (bitmap) mode.

Output is in TI-Artist format or raw image/pattern dump.

The article Modern Graphics on the 9918APDF gives an interesting overview on the techniques used in Convert9918.

(Author: @Tursi)


GraphiCV win/linux/osx

Sprite Editor written in java. Draw your sprites on the PC and export them for use in Extended Basic and Assembler.

Also supports export to Colecovision C format.

Work with multiple sprite “layers” for creating multi-colored sprites.

Click here for the GraphiCV development thread on atariage.

Source code is also available at github. Check here.

This utility needs the Java Runtime Environment available for free at Oracle.

(Author: @unhuman)


Magellan win/linux/osx

TI-99/4A map editor written in java. This is the latest, updated, unofficial version.

Draw your maps/screens on the PC and export them for use in Extended Basic and Assembler.

Has a rich feature set: Import character set from ‘.PNG’ or ‘.GIF’ file, copy & paste, drawing functions, support for half-bitmap mode, Export in XB display merge format, etc.

Possibility to export maps as data statements for Extended Basic and Assembler, binary export also possible.

Click here for the Magellan development thread on Atariage

This utility needs the Java Runtime Environment available for free at Oracle.

(Author: @The Codex). Enhanced by @retroclouds, @sometimes99er, @Asmusr.


Sprite Editor TI-99/4A

TI-99/4A sprite editor written in C99. Runs from Editor/Assembler #EA5.

Draw your sprites in an emulator or on the TI-99/4A machine.

The zip file contains both the files for use in emulator and a TI disk image for easy transfer to the TI-99/4A.

README file with detailed instructions included.

You can see the Sprite Editor at work building some sprites: Jet Set Willyvideo and Parsecvideo.

(Author: @Willsy)




VGM player

Compresses VGM files into a format that can be played back on the TI using the included player from C and assembly.

(Author: @Tursi)



Fully featured PC tracker for arranging music for the SN76489 and compatible sound chips. Can export to VGM and other formats.

(Author: KonTechs/Martin)


Sound List Ripper

PC tool for ripping and playing back sound lists from TI files. Supports basic editing of sounds lists.

(Author: @Asmusr)


Sound list player

Plays back sound lists from XB and assembly.

(Author: @matthew180)


Advanced Sound List Player

TI tools for editing and playing back advanced sounds lists.

(Author: @marc.hull)




QBOX Pro win

QBOX Pro is the windows software that converts WAV files to LPC speech data for playback on the TI-99/4A speech synsthesizer.

This is a 16bit windows application but it still runs in Windows 2000/XP/Vista.

It requires the BWCC.DLL library which can be found here.


BlueWizard osx

LPC analysis tool for the Texas Instruments TMS5220 chip. Replacement for QBOX Pro. Has very good speech quality.

Source code and pre-built install image for OS X can be found on gitHub here.

Discussion thread on Atariage available here.

(Author: @patrick99e99)


Python Wizard unix/win

This project is a python port (command line version and GUI) of the great macOS tool BlueWizard.

It is intended to convert (voice) audio streams into LPC bitstreams used in the TMS 5220 chip or e.g. in the Arduino library Talkie.

Now you can generate your own LPC streams and make your chips say the things you want them to.

(Author: @deladriere)


TI Synth Editor win

TI LPC speech pattern exploration and editing app in the spirit of the venerable Speecoder.

Watch the “How To” video to create custom speech synth here

(Author: @pixelpedant)




Notepad++ win

Notepad++ is a free source code editor that supports several languages.

Runs in Windows environment.


Notepad++ syntax highlighting file win

Syntax highlighting file for Assembler and Extended Basic to be used with the Notepad++ text editor.

6. Tutorials



Assembly language

Building a multi-bank ROM image PDF

Tutorial on compiling a 32K bank-switched cartridge ROM image starting from assembly source code (deref utility included).


How to implement an assembly sound player for XB web

Very well written tutorial on how to implement an assembly sound player for Extended Basic.

It covers the tools needed and steps involved.


Commented assembly source code

Not a tutorial in the classical sense, but the commented source codes of the below games should help you get the idea.

Pitfall! source code ZIP

Munchman source code PDF

TI invaders source code PDF

TI Invaders source code TXT

PARSEC source code PDF

Moon Mine source code PDF

Hopper source code PDF


Thank you @Ksarul for your OCR work on the PARSEC source code.

Thank you @Stuart for your OCR work on the TI-Invaders source code and tweaking it for assembly with Winasm99.

Thank you @dphirschler for pointing me to Hopper and Moonmine source code.


TMS9918/TMS9928 Video Display Processor

TMS9918/9928 video modes video

Video tutorial explaining the supported graphic modes of the video processor used in the TI-99/4A.


TMS9918/TMS9928 Sprites and Characters video

Video tutorial about the use of sprites and character patterns in the different video modes.


TMS9918/TMS9928 How to create a bitmap title screens video

Video tutorial on how to create a bitmap screen for games.


Speech Synthesizer

Convert WAV file for playback using speech synthesizer video

Video tutorial on how to use QBOX Pro to convert a 8kHz mono WAV file to LPC speech data

for playback on the TI-99/4A with the speech synthesizer device.

It shows how to embed the LPC byte stream into your own assembly language program.



The Wilhelm Basic compiler video

Video tutorial on how to compile a basic program to assembly language.

(Author: @Opry99er)


File transfer

(TI99->PC) RS232 File Transfer video

Video tutorial on file transfer from the TI-99/4A to the PC using a serial connection cable.

(Author: @Opry99er)


(PC->TI99) RS232 File Transfer VIEW PART 1 / VIEW PART 2 video

Video tutorial split in 2 parts dealing with file transfer from the PC to the TI-99/4A using a serial connection cable.

In detail: DL a game from TI Gameshelf, Use ARC303G to unarchive it, Test in Classic99, Transfer using QModem and MFM, Running game on TI.

(Author: @Opry99er)

7. TI-99/4A related websites



TI-99/4A @ wikipedia

Introduction and basics of Texas Instruments TI-99/4A Home Computer.



Wiki with information on MESS and its multicart format (RPK). Home of the TI-FAQ.


Thierry Nouspikel’s Tech Pages

Probably the best TI hardware and software tech page. It has a wealth of technical details on all things TI-99/4A.

This includes GPL, GROM, keyboard scanning, speech, etc.

You can also download the full site as a zip file for offline viewing.


Mainbyte’s home of the TI-99/4A

Very good tech site with many detailed pictures and reference area.

Includes various projects for upgrading your TI-99/4A, e.g. build a supercart cartridge.


Jon’s hexbus page

Several hardware projects including pictures. Home of the 64K bank-switched cartridge project.

(Author: @acadiel)



New website run by Matthew of the Atariage group. The site covers many new hardware projects as the F18A FPGA based VDP and Bank-switch mini 256K.

There’s also a store where you can buy cartridge PCB’s and other funky stuff.

(Author: @matthew180)


The nanoPEB & CF7+ Website

The official website. Has the documentation, tools and some source code of the popular TI-99/4A Compact Flash device.



TurboForth.net is the companion web site for the TurboForth system written in TMS9900 Assembly Language by Mark Wills for the Texas Instruments TI-99/4A computer.


TI projects page

Several hardware and software projects for the TI-99/4A.

Home of TI-99Dir, TI99HDX and several other must-see projects.

(Author: @F.G. Kaal)


TI-99/4A Home Computer Book Archive

Site where you find many books about the TI-99/4A not seen elsewhere, all collected by @airernie and now hosted by @acadiel

(Author: @airernie)


TI-99/4A Game Shelf

Provides a gallery of interesting games with images of the opening screen as well as an

in-play snapshot, along with a brief review tested on a real TI 99/4A system. Hardware

requirements are also listed. Has many good Extended Basic games.

(Author: @Vorticon)



WHTech is the primary archive – though it’s a bit overwhelming.

But pretty much all software, hardware docs, etc, are available there.



Site with useful file archive and forum functionality.



Covers all TI devices, including calculators.

TI-99/4A FAQ: PC to TI transfers with stock RS232/nanopeb and HDX server

You need:

TI-99/4a with either a RS232 card (TI and Corcomp have been tested, someone needs to test a myarc card) OR a nanopeb.

CFHDXS1 software on the TI OR a XB27 suite cartridge which has that software included as option U.. You can order both of these on arcadeshopper.com for a reasonable fee.

A rs232 cable (for the TI RS232 card) or a null modem cable (for the nanopeb) with the right ends on it for the PC side and the TI side.

A PC with a REAL RS232 port or a quality USB to RS232 adapter. Cheap new ones tend to have issues. I picked up a nice 25pin one at the local recycler that works great! A rs232 card for a desktop costs less than $20 on newegg/amazon.

Connect the cable from the PC to the TI. Remember that you use a straight through cable for the TI cards, and a null modem cable for a nanopeb. That’s because the nanopeb maker decided to put a PC style rs232 port on it so it’s backwards from a TI port.

PC Side:

go here: http://hexbus.com/ti99geek/

Click on projects then TI99HDX Server, download the server software latest version. Install on your PC somewhere you can find it. (I did C:/hdx/)

Run this program it looks like this:

Select Options and point the TI99 files directory to a directory you store FIADS or v9t9 format files into, if you don’t have one, for simplicity make a C:\tifiles directory and use that.

Select Options and select the correct COM Port under Communications Settings.

Also get the ti99DIR file manager software from that site and install that on your PC. Point one side of it at that same directory (C:\tifiles or whatever directory you picked above) you do this by hitting file, then select directory.

Point the other side at your downloads folder or your ti disks folder where you store disk images and downloads for the TI. whatever applies in your situation. You select which side you want to work with by clicking on it with your mouse and it will highlight.

You can then click into disk images and archive files and copy the individual files to the tifiles directory.. This is important as that is the file directory you will see on the TI-99/4A.. You can shift-click files to select groups then right click to pick copy. On the tifiles side you will note that the files either state they are TIFILES or V9T9 files on the right side of the listing. If they are not V9T9 files, you must convert them with the tools menu, convert TIFILES to V9T9 file.

Leave HDX server running on the pc..

TI Side:

Open CFHDXS1 with editor assembler, funnelweb, xb loader, dm2k, etc.. OR insert the XB27 cart and hit U.

At this point you should get a fun message to the effect of ” Ti99Hdx: <TI99/4a Initialized, HDX DSR version 02>” on the hdx server software on your pc. If you do not get this message you have either a cable problem OR a rs232 problem.


Hit any key on the TI and then enter HDX1. in the SRC: prompt this should give you a listing of the files in the tifiles directory on your PC. You can select files with INSERT (Fctn-2) and then hit PROCEED (Fctn-6) to pick copy.. then enter the TI disk drive you wish to copy too DSK1 etc.. in the DST: prompt and it’s copying files from your PC to your TI.

For more help with CFHDXS hit H when it is running and it will display it’s help screen.

Reverse the SRC and DST to copy the other direction.

Classic99 will read these files if you copy them into the DSK folders, alternatively you can just point HDX server to use the DSK1 folder under your classic99 directory and files can be used there directly.


TI-99/4A FAQ: Maintenance – Console disassembly

TI-99/4A Console Disassembly

This shows how to disassemble the console for maintenance or for other modifications. The only tools you really need is a Philips screwdriver and some heat sink compound.

Please make sure that all wiring and soldering is double checked before re-applying power. Though computer components are pretty hardy some do not take to being wired up backwards or incorrectly. I have done my best to make sure that all diagrams and instructions given here are correct, but I can not be responsible for any damage an incorrect upgrade might cause. Also keep in mind that this will probably void any warranty :>).

To get started disassembling the console you will need to remove the switch extension.

Just pull the switch extension straight out as shown by the arrow in the above picture. It simply snaps in and out.

The next step is to remove the 7 screws which holds the consoles two halves together. The best practice is to lay the console on a towel so you do not scratch or dent the soft aluminum covers, or scratch the plastic on the newer beige models.

You are now ready to remove the bottom of the console. All the internal parts are fastened to the top of the console. Next remove the power supply. It is fastened by 2 screws shown by the two arrows in the above picture.

After the 2 screws are removed, pull out the power supply and turn it over. The arrow points at the connector which connects the power supply to the motherboard. Some earlier models had the connector halfway between the motherboard and power supply. Squeeze the clip and pull the connector from the power supply. This connector can only go back on one way (unless you try really, really hard).

Now you are prepared to remove the motherboard and keyboard. The keyboard is held in by 4 screws shown by the yellow arrows, and the motherboard is held in place by 3 screws shown by the black arrows.

Now you are ready to remove both of these components. They should just pull right out of the case. Be careful handling both pieces at this point as you don’t want to break a wire on the keyboard connector.

This pictures shows the 3 main components of the TI-99/4A. In this picture I have unplugged the keyboard from the motherboard.

We are now ready to remove the shielding from the motherboard. The first step is to remove the cartridge extender, it just pulls out. Next remove the two clips which also just pull out.

On the end of the motherboard you will notice a copper shield which fits around the expansion end of the motherboard. Some motherboards use 4 screws while some only use 2. This one happens to use 2 screws. Remove all the screws holding the shielding. Be careful with these screws, particulary when re-assembling as you can easily strip them, and they are very small.

To finish the removal of the shielding you will need to remove 3 bolts. They are shown by the arrows in the above picture. They do have small lockwashers, so be sure to keep an eye out for them when you remove the nuts. BE SURE to notice the direction the bolts are inserted, as on some motherboards if you put them in “upside down” the case will hit them, and not go all the way together.

This picture shows the motherboard in all it’s 16 bit glory! The arrows show the heat sink and video chip. You will probably notice that the heat sink material has dried up. I suggest cleaning the old off and applying new heat sink compound before re-installing the shielding.

To re-assemble the console, you just need to reverse the steps above with a few things to keep in mind.

One, is to make sure the second part of the switch is in it’s correct position. The above picture shows this. This part needs to be in it’s correct slot before re-installing the power supply. The switch on the power supply must fit in the square on this piece. Also the LED fits into the slot shown by the arrow above.

Another is to make sure that you have all the wires routed correctly. They pretty much will only go one way but you don’t want to pinch any of the wires. You can use the above pictures to see how they go.

Remember to put the cartridge extender back in, I have put several of the consoles back together only to find this part sitting on the bench. Makes it tough to use any cartridges :>).

The last thing to do is to put the sliding cover back in on the expansion slot in the case. Though leaving this out will not cause any issues, any good TI’r would be embarrassed not to have this installed. The picture above shows this part. You can usually find this part laying on the floor somewhere.