DATAMATH CALCULATOR MUSEUM
Texas Instruments TI-81
|Date of introduction:||1990||Display technology:||LCD dot matrix|
|New price:||$110||Display size:||8 * 16 characters|
|Size:|| 6.8" x 3.1" x 0.85"
172 x 80 x 21 mm3
|Weight:||5.8 ounces, 172 grams||Serial No:||0935021|
|Batteries:||4*AAA||Date of manufacture:||mth 09 year 1990|
|AC-Adapter:||Origin of manufacture:||Taiwan (I)|
|Precision:||13||Integrated circuits:|| CPU: Toshiba T6A49A
Display: 2*Toshiba T7778A, T7900
|Program steps:||2400 Bytes||Courtesy of:||Joerg Woerner|
the famous TI-81 Texas Instruments entered the market of Graphing calculators.
Instead of the traditional 1-line display this kind of calculator offers a dot
matrix display with 64 * 96 addressable pixels. In the normal calculator mode up
to 8 lines of text information are shown. The TI-81 traces back to the Casio fx-7000G,
the world's first Graphing calculator.
The main features of the TI-81 in a short summary:
|• Graphing of up to 4 functions at one time.
• Parametric graphing to analyze up to three parametric equations.
• Manipulation of three matrices with dimensions of 6*6.
• One- and two-variable statistical analyses with up to 150 data points.
• Up to 37 programs with a total of 2400 bytes.
Please notice that this TI-81 from an early manufacturing series lacks a backup battery. The TI-81, like all Texas Instruments graphing calculators including even the latest TI-84 Plus Silver Edition, store the user program, user data and even calculator and display settings in a volatile C-MOS memory. To avoid the lost of the memory while replacing the main batteries, the mentioned calculators use an additional, coin-shaped, backup battery. Please read the warning in the 1st edition of the TI-81 Graphics Calculator Guidebook.
The TI-Nspire, introduced July 2007, was Texas Instruments' first
graphing calculator using non-volatile Flash memory to maintain the information
stored in the calculator even with low or empty main batteries.
From a technical aspect the TI-81 combines the 8-bit hardware architecture known from the Financial Investment Analyst FIA-10 and the enhanced capabilities from the TI-95 Procalc.
The hardware of the TI-81 is similar to a lot of other products: An 8-bit microprocessor of the Z80 family, a huge ROM of 128k Byte capacity, a RAM of 8k Byte size and a driver for the LCD display. You'll find similar architectures with just another balance of RAM and ROM capacity:
|Spell-Checker||128k Byte||2k Byte||RR-1|
|Data Bank||64k Byte||64k Byte||PS-6700|
|Graphing calculator||64k Byte||8k Byte||TI-81|
|Modern graphing calc||512k Byte||32k Byte||TI-83 Plus|
Dismantling this TI-81 calculator from the first series reveals some surprises:
|• The main electronics is centered around a Toshiba
Specific CPU instead the T6A43 found in the final TI-81 calculators.
• The display drivers are Toshiba T7778A resp. T7900 chips instead the
later T6A39 resp. T6A40 chips.
• We miss indeed the backup battery but the mounting space is obviously
astonishing to us is the find of the Toshiba T6A49A Application Specific CPU in
this early TI-81, the common version with
backup battery uses a T6A43 chip. We assume that the T6A49A had a serious bug
and was replaced with the proofen T6A43 from the PS-6600
Organizer. (Comment: The PS-6600 was introduced in 1992, two years after the
Comparing the display boards of different TI-81 models reveals almost identical printed circuit boards (PCBs) populated with either the Toshiba T7778A column drivers and T7900 row drivers or the probably identical T6A39 and T6A40 chips.
Late in 1991 the internal construction of the TI-81
was revised and missing backup battery was added. Please find a detailed
overview of the different hardware architectures of the TI-81 generations
between 1990 and 1995 here.
Fellow collectors - if you own a TI-81 w/o backup battery, please report us the serial number and date code from the back of the calculator plus the ROM-Version for our TI-81 1st gen Database.
Don't miss a rare TI-81 Engineering Sample, manufactured probably in April 1990.
A special "teacher version" called TI-81 VSC combines the standard TI-81 features with a fixed connection to a ViewScreen panel via a flat-ribbon cable. Placing the panel on the overhead projector enlarges the image of the handheld screen so that each student can follow along.
The TI-81 was mentioned in TI's press release dated August 15, 2002 to celebrate the 35th anniversary of its invention of the electronic calculator.
Take a short trip to the TI-78, TI-88 and the Hewlett-Packard HP-41C!
The market of graphing calculators was immediately dominated by Texas Instruments and from time to time we get some figures of the accumulated shipment since the introduction of the TI-81. We noted:
|Date of press release||Accummulated shipment|
|Sept. 6, 2000||20,000,000|
|July 22, 2003||25,000,000|
You can check the ROM version of your TI-81 using the following key sequence and reading the number on your screen:
[2nd] [TEST] [ALPHA] [S]
Information provided by ticalc.org
and Xavier Andréani.
The TI-81 is permitted (as of September 27, 2007) for use on SAT,
and AP exams but
is not recommended for the AP exam.
shipping more than 20 million graphing calculators
DALLAS, September 6, 2000
Texas Instruments, leaders in classroom technology, announced today that they have shipped more than 20 million graphing calculators with this Back-to-School season. Since entering the graphing calculator market in 1990, TI has consistently led the graphing calculator segment and experienced firsthand, the growing trend of classroom technology.
While computers are increasingly used in schools, graphing calculators are the most pervasive form of technology in student's hands across the United States . Graphing calculator sales have been averaging about 10 percent growth for the last several years and are rapidly gaining favor in other countries.
"We're constantly hearing people tell us that they used our products in high school." said Tom Ferrio, vice president, Texas Instruments, "They're always amazed at the power and capabilities that the tools now have."
Graphing technology has changed dramatically since TI first introduced the TI-81 in 1990. Products now boast operating systems that can be electronically upgraded via the Internet, calculator software applications (Apps) for adding specific functionality, and peripherals for data collection and real-world experimentation.
"I've used graphing technology in my classroom for five years," said Melissa Rowe, math teacher, South Grand Prairie High School. "The advancements in the tools have helped my students advance deeper into the math and master more complex subject matter than ever before."
In the last decade, TI has introduced 11 graphing technology products, many of them improved versions of their predecessors. The current product family includes the most popular graphing product in the United States, the TI-83 Plus, for high school and college math and science; the TI-73 for middle grade students; and the TI-89 and TI-92 Plus for advanced mathematics through college and graduate studies.
Over 30 software Apps are available for the above products, with many available to schools and students free. Some Apps even provide actual curriculum in electronic format that compliments classroom textbooks.
To celebrate it's 10th Back-To-School season, TI is offering four TI-83 Plus Apps free with product purchase for a limited time. (More information at www.ti.com/calc).
|TI-81 Graphics Calculator
Copyright © 1990 by Texas Instruments Corporated.
B-2: Effects of Replacing the Batteries
The calculator cannot hold data in its memory when the batteries are removed or become discharged. Replacing the batteries has the same effect as resetting the calculator.
1-28: Resetting the TI-81
Resetting the TI-81 restores the memory to the factory settings. Because there are operations that clear only selected portions of memory, the TI-81 should be reset only under special circumstances, such as when it is first acquired.
1-28: Results of Resetting
When you reset the TI-81:
|The contrast setting is set to 7.||The MODE setttings are set to the defaults.||The viewing rectangle is set to the standard defaults.||All variable values are set to zero.||All statistical data is erased.||All matrix values are set to zero.||All matrix dimensions are set to 6 by 6.||All functions in the Y= list are erased.||All programs are erased.||Zoom factors are set to 4.||Rand is reset to the factory seed of 0.|
|Serial Number||Date code||ASIC||ASIC code||ROM-
|none||none||Toshiba T6A49||9018||1.0||Joerg Woerner|
|0935021||I-0990||Toshiba T6A49A||9030||1.1K||Joerg Woerner|
|1107787||I-1190||Toshiba T6A49A||9037||1.1K||Marc Ferrer|
|0309273||I-0391||Toshiba T6A43||---||1.5K||Jérôme Quartanar|
|0519319||I-0591||Toshiba T6A43||---||1.6K||John Meine|
|0615087||I-0691||Toshiba T6A43||---||1.6K||Bas Bekema|
|0748924||I-0791||Toshiba T6A43||---||1.6K||Bob Vargo|
|0917651||I-0991||Toshiba T6A43||9118||1.6K||Joerg Woerner|
|1239636||I-1291||Toshiba T6A43||9145||1.6K||David Petty|
If you have additions to the above article please email: email@example.com.
© Joerg Woerner, January 19, 2003. No reprints without written permission.