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.

TI-99/4A FAQ: Maintenance – Cleaning Cartridge Port

Cleaning Console Port

The only way to really give the port connectors a good cleaning is to remove the port from the console. This might seem like a lot of trouble but more than likely this should be the only cleaning it will need for a very long time. For instructions on how to disassemble the console go Here

The above picture shows the cartridge port with the cartridge door open. You can’t really tell from the picture but this port is quite dirty.

To clean the port use isopropyl alcohol or Tape head cleaning solution. Also use a standard business card or index card (cut slightly to fit into the port), folded in half, and a q-tip to apply the cleaning solution to the end of the business card.

Remove the cartridge port from the motherboard by pulling it straight out. You do not need to remove the metal shielding from the motherboard to do this.

The above picture shows the port. The two arrows are pointing at the felt “cleaning strip” and the cover for it.

The idea behind the felt pad was to act as a cleaner for the cartridge contacts when you plugged in a cartridge. Most suggest that this felt pad be removed as it does more harm than good. It just seems to collect more dirt then it ever cleans off.

Removing the cover and felt pad is a simple process and the two pictures show how to do this.

The picture above shows the cover and felt pad removed from the port connector. As you can see the felt pad has seen better days.  Do not re-install the felt pad. This is just to show what it might look like.

The next step is to clean the internal contacts on the port connector. Use a folded business card or index card and apply isopropyl alcohol or cleaning fluid to the end which will be inserted into the port. Do this several times and then use a new clean card and repeat the cleaning. Repeat this until the cards come out clean.

TI-99/4A FAQ: Mini Memory

Mini Memory

The Mini-Memory Cartridge is a neat device that allows one to actually store small programs in the cartridge. It also comes with an assembly editor, which os how a lot of TI-99/4A users first worked with assembly language.

This is the “insides” of the Mini-Memory Cartridge. Notice the battery which kept a small charge on the memory chips so it could keep programs even after it was removed from the computer. If you pick one of these up, you will most likely have to change this battery. Here is a link to the instructions for doing just that: http://www.mainbyte.com/ti99/minimem/minimem.html

By Ira McComic

You know looks can be deceiving. For example, who would ever suspect that a bespectacled, mild-mannered reporter for the Daily Planet could actually hop over a skyscraper with a single bound? In the same way, there’s a lot more to TI’s new Mini Memory Command Module than meets the eye. It appears to be just a normal, garden-variety Command Module*the same size, same shape, the same black unassuming case. But lying inside that plain cover are the ingredients to convert your TI Home Computer from a good BASlC programming machine into a trim and efficient assembly language instrument.

The name itself is a clever disguise. “Mini” Memory, indeed! If you believe that all there is inside that plastic case is just a little bit of memory, then you’d probably believe the Trojan Horse was nothing more than an overgrown child’s riding toy! There’s actually 14K bytes of memory sitting in there. 4K bytes of RAM, 4K bytes of ROM, and 6K bytes of GROM.

RAM (read/write) memory is the kind of memory in which our programs are stored. You know how it works. You write a program and it’s stored in RAM. When you turn off the computer, the program you wrote is gone, unless you had the foresight to save it on a cassette or diskette before you flipped the switch on the computer. Now, here’s the first surprise from the Mini Memory Module: You can store a program or data in its RAM and your program or data is not lost when you turn off the computer. In fact, you can store a program or data in the Mini Memory Module’s RAM, turn off the computer, remove the module from the console and carry it around with you, just as you can a cassette or diskette. This seeming miracle is possible because the module contains its own life-support system. A battery inside the module keeps the contents of the RAM alive. The RAM components are CMOS devices and are power misers. It only takes a small trickle of current to keep the little critters alive when they are not being used. The battery inside the module should last you a couple of years. When you finally need a new battery, you can exchange the module for a new one.

Battery-backed RAM can be real handy, if you think about it. Just imagine*you can write a new program, store it in the Mini Memory Module, turn off the computer, yank out the module, zip over to your friend’s house where you plug in the Mini Memory Module, and instantly load your new program into your friend’s computer so he can admire your handiwork. No cassettes, no disks, no messy cables, and no long waits.

Besides the battery-backed RAM, the Mini Memory Module also has 6K bytes of GROM (Graphics Read Only Memory) and 4K bytes of ROM (Read Only Memory). Inside the GROM and ROM are seven additional TI BASIC subprograms, including PEEK and POKE.

This same GROM and ROM also gives you access to many of the computer system’s routines from assembly language programs. There’s still more. As you develop your assembly language programs, you’ve got some help. The ROM contains a powerful program debugger called EASY BUG which you can use to exterminate those pesky �logic vermin� which sometimes infest programs.

At this point, you may be saying to yourself, “What good does all this assembly language access and debugging stuff do me, anyway, without an assembler?” Glad you asked. Here’s the next bit of exciting news. The Mini Memory Command Module comes with a cassette which contains an assembler. You can load this assembler into memory, enter assembly language statements, and have the assembler translate the statements into 9900 object code for you.

See what I mean? There’s a lot more to this Mini Memory Module than its alliterative name. . . The Mini Memory Module is, indeed, full of pleasant surprises. Here’s what we’ve discovered so far: First, it’s got 4K bytes of battery-backed RAM where we can save programs and data. Secondly, it’s got 10K bytes of ROM and GROM which contain additional TI BASIC subprograms, provide a passport into the computer system’s routines, and hold the EASY BUG debugger. Thirdly, the Mini Memory Module comes with an assembler so you can create your own assembly language programs. That ought to be enough to even coax a smile out of a mother-in-law, but there is still one more surprise: On the same cassette with the assembler is a bonus. It’s a demonstration program which produces a fascinating color burst of patterns on the monitor or TV display.

Let’s explore these items one at a time.

FILE STORAGE

Probably most persons will use the Mini Memory Module most often for temporary storage of programs and data. You can think of the Mini Memory Module as a very fast access storage device.

Additional Files

When you have the Mini Memory Command Module plugged in, the 4K-byte RAM has the file name MINIMEM for TI BASIC program and data storage. The RAM occupies physical addresses 28672 through 32767 (hexadecimal 7000 through hexadecimal 7FFF). You can save programs in this file and load programs from it. (For example, to save a TI BASIC program, just enter the command SAVE MINIMEM.) You can also store data in this file using the file specifications available for any TI BASIC file. For example, the following statements open the Mini Memory file and store four data values in the file.

OPEN #3 :”MINIMEM”,RELATIVE,FIXED,UPDATE
INTERNAL
PRINT #3: A,B,C,D

With the Mini Memory Module you can also access a second new file. EXPMEM2 is the name of a 24K-byte memory file located in the 32K Memory Expansion unit. EXPMEM2 is only available, however, if you have the Memory Expansion unit connected to your computer and turned on.

ROM AND GROM PROGRAMS

Inside the Mini Memory Command Module’s 10K bytes of “firmware” (that’s computer talk for ROM and GROM) are additional TI BASIC subprograms, hooks to connect assembly language programs to the computer system’s programs, and a program debugger for machine language programs.

Additional TI BASIC Subprograms

Seven additional TI BASIC subprograms are yours with the Mini Memory Module. These subprograms are PEEK, PEEKV, POKEY, CHARPAT, INIT, LOAD, and LINK.

The PEEK subprogram reads bytes of CPU RAM data and copies the data directly into TI BASIC variables. For example, the statement:

CALL PEEK (8192,A,B,C(8))

reads three bytes of data from address 8192 and up, and assigns the values read to the variables A, B, and C(8).

The PEEKV subprogram reads bytes from VD1� RAM. It works exactly like PEEK, except PEEKV accesses VDP RAM instead of CPU RAM.

The POKEy subprogram stores data values into VDP RAM. For example, CALL POKEV(784,30,30,30) writes the value 30 to VDP RAM locations 784, 785, and 786.

The CHARPAT subprogram reads a 16-character pattern identifier that specifies the pattern of a character code. For example, CALL CHARPAT(68,D$) places the pattern defining character code 68 in the string variable D$.

The three TI BASIC subprograms INIT, LOAD, and LINK interface assembly language programs and TI BASIC programs.

The INIT subprogram initializes the CPU memory for assembly language programs. The LOAD subprogram serves two purposes: it loads assembly language object files into CPU memory; and it loads data into CPU memory.

There are two forms of the LOAD subprogram. One form is used to load an object file from a storage device into memory and the second form is used to load data directly into CPU memory. For example, the statement CALL LOAD (“DSK1. DEMO”) loads the file DEMO from the diskette in Disk Drive 1.

The second form of the LOAD subprogram is a POKE function for CPU RAM. For example, the statement CALL LOAD (8197,85,40) loads the value 85 into memory location 8197 and the value 40 into memory location 8198.

The LINK subprogram passes control and, optionally, a list of parameters from a TI BASIC program to an assembly language program. For example, the statement CALL LINK (“PROG1”,A,E(9)) passes control from a TI BASIC program to an assembly language program named PROG 1 and passes the variables A and E(9) to the program.

Access to System Routines

The utility routines resident in the Mini Memory Command Module can be called from an assembly language program to access machine resources and interface with the TI BASIC interpreter. It’s fair to warn you that the use of these routines requires a knowledge of the routines themselves and the organization of data used by the routines. You can get additional information about these routines from the Editor/Assembler owner’s manual, (This is an excellent book, by the way. It’s packed with inside information on the Home Computer’s architecture.)

Two types of access programs are resident in the Mini Memory Command Module. One program contains a collection of system utilities with which to link to ROM/GROM routines, perform a keyboard scan, access the VDP, etc. The individual utility programs are classified as either a “Standard Utility” program or an “Extended Utility” program.

A second program contains TI BASIC interface utilities with which an assembly language program can access variables passed through a CALL LINK statement in a TI BASIC program. This program also contains an error-handling utility to return exceptions to a TI BASIC program.

Standard Utility Programs

Here’s a list of the standard system utilities which become accessible with the Mini Memory Command Module.

* VDP Single Byte Write * write a single-byte value to a specified VDP RAM address.
* VDP Multiple Byte Write * write multiple bytes from CPU RAM to VDP RAM.
* VDP Single Byte Read * read a single byte from a specified VDP RAM address.
* VDP Multiple Byte Read * read multiple bytes from VDP RAM into CPU RAM.
* VDP Write to Register * write a single-byte value to any of the VDP RAM registers.

* Keyboard Scan * scan the keyboard and return a keycode and status. This routine can also read the position of the Wired Remote Controller.

Extended Utility Programs Extended utilities are provided to access routines in the console CROMs and ROMs. These utilities are GPLLNK (link to GPL routines in GROM), XMLLNK (link to routines in ROM), and DSRLNK (link to Device Service Routines). The Mini Memory Module manual (try to say that three times real fast) advises that you ought to know what you’re doing before you access these routines.

GPLLNK Routines The GPLLNK routines are as follows:

* Load Standard Character Set * load the standard character set into VDP RAM.
* Load Small Character Set * Loads the small character set (for the 40-column “Text Mode”) into VDP RAM.
* Execute Power-Up Routine * Initializes the system as if the computer had just been turned on.
* Accept Tone * Issues an accepting tone for input.
* Bad Response Tone * Issues a bad-response tone warning.
* Bit Reversal Routine * Provides a mirror image of a byte of information. (This is often handy to form a mirror image of a character definition.)
* Cassette Device Service Routine * Accesses a cassette tape recorder/player as a storage device.
* Load Lower Case Character Set * Loads the lower-case character set into VDP RAM.

A number of floating point routines are also available through GPLLNK. Here they are:

* Convert a floating-point number to an ASCII string.
* Compute the greatest integer contained in a value. * Raise a number to a specified power.
* Compute the square root of a number.
* Compute the inverse natural logarithm of a value.
* Compute the natural lo~ of a number.
* Compute the cosine of a number.
* Compute the sine of a number.
* Compute the tangent of a number.
* Compute the arctangent of a number.

XMLLNK Routines

Routines in the console ROM can be accessed through the XMLLNK routine. The following routines can be called from an assembly language program using XMLLNK.

* Floating-point addition.
* Floating-point subtraction.
* Floating-point multiplication
* Floating-point division.
* Floating-point compare.
* Floating-point stack addition.
* Floating-point stack subtraction.
* Floating-point stack multiplication.
* Floating-point stack division.
* Floating-point stack compare.
* Convert a string to a number.
* Convert a floating-point format number to integer.
* Push a value onto the value stack.
* Pop a value from the value stack.
* Convert an integer number to floating-point format.

DSRLNK Routines

DSRLNK links an assembly language program to a Device Service Routine (DSR) or subprogram in ROM. As with GPLLNK and XMLLNK, TI cautions you to make sure you know what you are doing before using DSRLNK.

A DSR is a machine language program that TI has burned into ROMs found in each of its peripherals. Since each peripheral contains its own custom “operating system,” the TI-99/4 did not have to be designed to anticipate future peripheral requirements*Ed .1

TI BASIC Interface Utilities TI BASIC interface utilities allow an assembly language program to read or assign values to variables passed in a parameter list from a CALL LINK statement in a TI BASIC program. These utility routines include argument-passing utilities and an error-reporting utility.

The following are the TI BASIC interface utilities.

* Assign a numeric value to a numeric variable.
* Assign a string to a string variable.
* Retrieve the value of a numeric parameter.
* Retrieve the value of a string parameter.
* Report an error. (The assembly language program can report any existing TI BASIC error or warning message upon returning to TI BASIC.

EASY BUG Debugger

Also inside the Mini Memory Module’s ROM is EASY BUG. EASY BUG is a versatile program development tool with which you can (1) debug your assembly language programs, (2) access the input/output ports of the computer, (3) load programs, and (4) store programs. And, as the name implies, it really is easy to use. -With EASY BUG, you can inspect and (optionally) modify the contents of CPU and VDP memory, display the contents of ROM, run assembly language programs from EASY BUG, directly access the peripheral devices which are connected to the computer via the 9900 microprocessor’s serial I/O port (the CRU), and save and. load programs on cassette.

LINE-BY-LINE SYMBOLIC ASSEMBLER

A line-by-line symbolic assembler on a cassette tape is supplied with the Mini Memory Module. It assembles assembly language statements and stores the object code directly into the 99/4�s CPU RAM. The assembler is a derivative of the line-by-line assembler used by the TM990/189 board (the University Module). You can make both forward and backward references to one- or two-character labels with the assembler. Each source statement you enter is immediately assembled into object code and stored into memory. Some source code is retained in a nine-page text buffer. You can scroll the screen to review previously entered lines of source code by pressing the Up- and down-arrow keys. The source program cannot be saved, however.

The line-by-line assembler occupies about 2K bytes. When it is loaded into the Mini Memory Module’s 4K byte RAM, you still have about 2K bytes of memory for your assembly language program.

Assembler Directives

The assembler recognizes seven directives:

* The AORG (Absolute Origin) directive establishes the location counter value to set the starting address of the assembled code.

* The BSS (Block Starting with Symbol) directive re- serves a block of memory without initializing the space.

* The DATA (Data Initialization) directive initializes a word or words of memory to a specific value.

* The END (End Program) directive terminates the assembler and causes a display of the number of unresolved references, if any.

* The EQU (Equate) directive defines a value for a symbolic constant.

* The SYM (Symbol Table Display) causes a display of all symbols and theft associated values in the program.

* The TEXT (String Definition) directive causes a string of characters to be translated into their ASCII code and stored as a part of a program.

[An assembler “directive” is a programming-aid command which directs the assembler to perform certain operations at assembly time. An assembler may execute many “instructions” (telling the microprocessor to perform single functions such as Add or Move) to satisfy one directive*Ed.]

DEMONSTRATION PROGRAM

Along with the line-by-line assembler on the cassette is an assembly language demonstration program called LINES which draws a colorful line design on the screen. The LINES program can be run only on the TI-99/4A Home Computer, however, because it requires the enhanced graphics processor contained in the TI-99/4A. [A forthcoming issue will carry an explanation of how the “bit map” mode (necessary for the LINES program) of the TMS99 WA Video Display Processor works*Ed

OPERATION

TI has a knack for creating complex and versatile programs that are still simple to operate; they’ve definitely done it again with the Mini Memory Module. When you plug in the module, turn on the computer, and pass the opening credits on the Master Title Screen, you are presented with a simple, three-choice selection screen. You can choose TI BASIC, EASY BUG, or MINI MEMORY.

If you select MINI MEMORY, you are presented with a second three-choice selection screen. You can choose to load an object program into memory and run it, run a previously loaded program already in memory, or re-initialize the module to prepare it for loading new programs or storing data, Pick a number, pluck a key and you’re off and running. It’s as easy as eating oatmeal cookies!

CONCLUSION

This has got to be one of the best deals around. There’s 4K bytes of RAM with battery backup so that all the good stuff stored in the RAM is not lost when you turn off the console or even when you remove the module. There’s 1OX bytes of ROM and GROM which give you seven additional TI BASIC subprograms (including PEEK and POKE), access to system routines from assembly language, and routines to allow you to interface assembly language programs to TI BASIC. You’ve got a user-friendly program debugger, a symbolic line-by-line assembler, and a captivating graphics demonstration program. All of this, plus S4 pages of docomentation for $99.95 (suggested retail price). With all this to offer, it’s really not too hard to see why there’s definitely more to the Mini Memory Command Module than meets the T-eye…

TI-99/4A FAQ: Supercart

The Supercart adds 8K of battery-backed RAM to the Editor/Assembler module. The utility of this device derives in large part from its capacity to provide E/A module menu access to assembly language software. In effect, this means you can write your own 8K battery-backed command module software.

Do it yourself projects:

  • http://www.mainbyte.com/ti99/supercart/supercart.html
  • http://www.mainbyte.com/ti99/supercart/supercart_4bank.html

Purchase a pcboard for this:

There were commercial products available on the market for a time in the 80’s as well.

 

TI-99/4A FAQ: Repairs and troubleshooting

My TI isn’t working right! help!

    • Keyboard issues
      • The keyboard is connected directly to the TI motherboard with a pin connector. This can become loose/dirty and may need cleaning/reseating. There is no logic within the keyboard is is merely shorting the keyboard lines when you hit the keys. keyboard_schematic.jpg
      • If your cable is damaged there are replacements available at http://www.arcadeshopper.com/under hardware/cables
      • Alpha Lock issue: With the alpha lock key on you are unable to use the up direction with the joysticks. Release alpha lock to play games OR do this fix: http://mainbyte.com/ti99/console/alpha_lock.html
      • What keyboard do I have? There were at least 5 manufacturers of keyboards for the 99/4a. http://mainbyte.com/ti99/keyboard/keyboard.html has good pictures/info/schematic.
      • keyboard_front.jpg
        • Mitsumi: These keyboards do not have any solder points except for the alpha-lock key connection and the ribbon cable.
        • Image result for ti-99 keyboard mitsumi
        • Alps and others: These keyboards have solder points on the back of the PCBoard keyboard_back.jpg
          • these keyboards sometimes have dirt/corrosion in the switches that can be cleaned with contact cleaner or alcohol.
      • Console just BEEPS
        • The start up routine of a 99/4a initializes the sound chip with a tone and then the rom boot routine shuts off the tone.. If it just beeps either there is a bad connection to a peripheral OR a board level issue that is causing the startup routine to “lock”. Check all socketed chips for good connection/corrosion etc and reseat.  Sometimes this is caused by a damaged 9900 and it will need to be desoldered and replaced.
      • Scrambled/Garbled screen graphics/text
        • 80% of the time this is VDP ram and it will need to be replaced.
          • Here is a great page on how to determine what RAM chip is bad: http://www.ninerpedia.org/index.php?title=Troubleshooting
            • Don’t use 4116 ram, it costs more than 4164 and uses more power/generates more heat. 4164 will last longer.  See this post for more info https://atariage.com/forums/topic/257923-replacing-4116-ram-with-4164-for-reliability/
            • VDP Ram is soldered into the motherboard and will need to be desoldered and replaced (suggest it is replaced with sockets and new ram inserted into the socket) this ram is TMS4116 static ram. Located in number 6 in this photo: http://mainbyte.com/ti99/hardware/big_mother2.jpg
            • The F18A VGA VDP replacement contains it’s own VDP ram so replacing the TMS9918a VDP in your 4/a with a F18A will also replace bad memory without having to solder..
        • On NTSC/USA machines TMS9918a VDP is the hottest component on the motherboard and this tends to end it’s life prematurely. Daily use consoles tend to have the VDP fry sooner or later. This chip is socketed so it is relatively easy to replace. It is covered with heatsync compound and there is a metal slug that sits on top of it under the RF shield on a original 4/a. On a QI model there is a metal heat-sync clipped to the 9918a.
      • Cartridges don’t work or don’t work reliably.
        • The TI cartridge port is the most used part of a console. It tends to get dirty and gummed up. Info here on cleaning carts and the port: http://mainbyte.com/ti99/minimem/cart_fix.html
        • Replacement cartridge port boards are available on ebay and from vendors.

TI-99/4A FAQ: Compatible computers

Compatible computers?

Myarc Geneve 9640

The Geneve 9640 is an enhanced TI-99/4A clone. It was sold by the company Myarc as a card to fit into the Texas Instruments TI Peripheral Expansion System. Released in 1987, it is in many ways similar to the earlier TI-99/8, which was in prototype form in early 1983. The Geneve 9640 was designed by Paul Charlton,[1] and the graphical swan on the boot up screen was designed by Mi-Kyung Kim.[2]

The Geneve 9640 features a 16-bit TMS9995 processor clocked at 12 MHz. A Yamaha V9938 video display processor (the same one used in the MSX2 family of home computers) provides 256 color graphics at a 256 x 424 resolution, 16 color graphics at a 512 x 424 resolution, and an 80 column text mode. Audio is produced via an SN76496 programmable sound generator, capable of producing three simultaneous square waves at sixteen different volume levels, as well as an additional noise channel that could produce either periodic or white noise in three different frequencies and at sixteen different volumes. An IBM PC XT compatible detached keyboard and a mouse are used for input. The Geneve 9640 is compatible with nearly all software written for the TI-99/4A. An adapter was made by a company named Rave to allow the sidecar-only Speech Synthesizer to be installed inside the Peripheral Expansion System.

SGCPU – Second generation CCU Card

Tomy Tutor

The Tutor contains a lot of the same hardware and software, and 9995 processor like the Geneve.. in fact Tomy games have been converted to run on the Geneve.

The Tomy Tutor, originally sold in Japan as the Pyūta (ぴゅう太) and in the UK as the Grandstand Tutor,[2] is a home computer produced by the Japanese toymaker Tomy. It was architecturally similar, but not identical, to the Texas Instruments TI-99/4A, and used a similar Texas Instruments 16-bit CPU.[3] The computer was launched in Japan in 1982, and in the UK and the United States in the next year.[4]

History

Produced by Matsushita, the computer was released in Japan in 1982 under the name Pyūta.[4]

Tomy described the Tutor, with 16K RAM, as good for games and education. The company stated that its documentation would let an eight-year-old child use the computer without adult supervision.[5]

One of the major flaws pointed out with the Tutor was not its hardware, but its marketing: the Tutor was announced as a children’s computer when in fact it was practically a cheap, evolved version of the TI-99/4A, even having a similar 16-bit CPU (the TMS9995, closely related to the TI-99/4’s TMS 9900);[3] other competitors in its price range still used 8-bit microprocessors.

The Pyūta Jr. was a console version of the Pyūta, released in April 1983,[6] and similarly was only sold in Japan.

In Japan, Tomy set a sales target of about 90,000 units and ¥5 billion revenue for the first year by selling Pyūta to elementary and junior high school students as a “drawing computer”, having nearly 40,000 units shipped in its first 4 months as of August 1982.[7][8] However, sales fell sharply when Nintendo released Family Computer (later deployed as Nintendo Entertainment System) in 1983 as a cost-effective option. In February 1985, Tomy ceased its production and withdrew from the market.[9] As of May 1984, a total of 120,000 units were shipped for domestic and export use in Japan.[1]

In the other hand, the Tutor did not sell well against the ZX Spectrum in the UK and the Commodore 64 in other countries outside Japan. It ended up being removed quickly from the market and replaced the following year by the Pyūta mk2 with a standard mechanical keyboard instead of the original “Chiclet”-style keyboard. However, the new model seems to have been sold only in Japan, and even then only for a short period of time.

Technical specifications

TI-99/4A FAQ: Software: Terminal Programs

What Terminal Software is there for the TI

Terminal Emulator II is a cartridge that will allow you to connect to RS232/1 or 2 at 110 and 300 baud.
This software has it’s own “terminal protocol” that allowed for changing character definitions and other cool stuff.
Runs on a stock console without memory expansion.

FastTerm was a popular terminal program that gave you basic terminal functions and xmodem transfers. 32k and cartridge image or disk system required.

Telco is the most full featured terminal program for the TI, it included multiple terminal (including ANSI but no color) and transfer protocols, phone book and auto dialer and many other features. 32k and disk system required

Term80 allowed you to have an 80 column terminal on your 99/4a with the stock VDP, hard to read but amazing! 32k and disk system required

Mass Transfer was a terminal program that worked well to send multiple files between computers. 32k and disk system required (included in XB27 suite) This is also one of the programs that has been updated to support telnet via TIPI see TIPI SOFTWARE for more info.

TIMXT is the latest terminal released allowing for up to 38000 baud full color ANSI terminal on a NanoPEB or TI rs232 card and 80 column text with the F18a VDP. 32k, rom load or disk system and F18a required. http://atariage.com/forums/topic/265573-timxt-terminal-emulator-dev/?do=findComment&comment=3761846

TI-99/4A FAQ: Software: Games

What are the best games for the TI-99/4A?

The best games are usually run in 32k from disk or use a large rom cartridge such as the 512k cart or the FlashROM99 or FlashGROM99 cartridges. Expansion RAM (32k) is a requirement for most modern home-brew games/demos.

The TI Gameshelf contains a database of all kinds of games including games that run from TI-Basic, Extended Basic and Assembly Language games that require a disk system and 32k. (see website links at the top of the FAQ)

There is a great game high score contest on the atariage forum that we showcase some of the best games for the 4/a every month and the winner of the high score contest usually wins TI software or hardware donated by the last month’s winner.

Rasumus and Sometimes99er are the most prolific home-brew game makers as of late and their software is featured here in the development forum. Cartridges for most of these are available at arcadeshopper.com

TI-99/4A FAQ: Software: Web Browser

A web browser? seriously?