Texas Instruments TI-88

Date of introduction:  Never
 (Announced: May 1982)
Display technology:  LCD dot matrix
New price:  MSRP: $350.00 Display size:  10 (8 + 2)
Size:  6.0" x 3.0" x 1.5"    
Weight:  8 ounces Serial No:  000337
Batteries:  1*AA-NiCd Date of manufacture:  wk 21 year 1982
AC-Adapter:  AC9133 Origin of manufacture:  USA (ATA)
Precision:  13 Integrated circuits:  CD 2901, CD2902,
 TP531C, CD5402 
Memories:  120-0    
Program steps:  0-960 Courtesy of:  Joerg Woerner
Download product announcement:   (US: 2.1 MByte) Download manual - PREVIEW ONLY:   (US: 4.2 MByte)

TI-88_CMP.jpg (124464 Byte)We wrote the year 1982 when the calculator manufacturer Texas Instruments printed the sales brochures of the TI-88. The printed papers promised the introduction of the TI-58C/TI-59 successor in the year 1983. Today we know more: The development of the TI-88 was finished, the manuals printed, the first pre-production calculators worked perfectly and someone canceled the whole project! Maybe one of the reasons was the powerful Hewlett-Packard HP-41C calculator.

Currently we know seven TI-88 that survived:

Owner Serial No: Date of manufacture
Joao Oliveira 4-30-1982 ATA wk 18 year 1982
Joerg Woerner 000337 ATA wk 21 year 1982
Marie Lisa Collas 000341 ATA wk 21 year 1982
Viktor T. Toth 001101 ATA wk 32 year 1982
Luis Gómez 002055 ATA wk 33 year 1982
Smithsonian Institute 002074 ATA wk 33 year 1982
Heinz Nixdorf Forum t.b.d. t.b.d.

Viktor T. Toth acquired his rare pre-production model on eBay in the year 2000 for an undisclosed amount of money. The TI-88 pictured in the Datamath Calculator Museum was sold by the first owner in June 2006 for $175.00 or half of the original MSRP of $350.00. Some of the information about the TI-88 is either from the sales brochures or the manual.

Compared with the TI-58C you'll notice some differences and similarities:

The display is alphanumeric and prompts system messages in readable English.
The Constant Memory™ covers program and user memory.
The Solid State Software™ concept allows the expansion of two cartridges, either application programs or user memory.
Beside the traditional programming a formula mode is available.
A real time clock adds time and date.
A small speaker produces sounds. 
A printer port accepts the PC-800 printer.
A Cassette Interface CA-800 allows the permanent storage of both programs and data with a tape recorder.

TI-88_D3.jpg (20905 Byte)TI-88_D2.jpg (21792 Byte)TI-88_D1.jpg (23881 Byte)It is a pity that the TI-88 with the perfect prompting system never made it to the market. The next calculators in the "Programmable/Scientific line" are the TI-95 PROCALC and the first Graphing calculator TI-81.

Interested in failed calculators? Don't miss the first SR-40 scheduled for release in 1975.

A Texas Instruments price list printed in July 1982 suggested these MSRP's:

Product MSRP (July 1982)

TI-88 Programmable Calculator


PC-800 Printer


CA-800 Cassette Interface


Constant Memory Modules CRAM


Solid State Software Modules CROM


Inside the TI-88

TI-88_PCB.jpg (184660 Byte)TI-88J_PCB.jpg (187260 Byte)TI-88J_PCB3.jpg (166957 Byte)Recently the Patent application US4447881 filed by Texas Instruments in the year 1980 was discovered from Juergen Dobrinski. Together with an inside view of the two TI-88 we understand now the calculator architecture. The design is centered around a 4-bit microcontroller called Master Controller with two associated 4-bit controllers responsible for the arithmetics and the I/O. We got a similar approach with two controllers already with the TI-55 II. The overall design consists of:

CD2901 (TP0485) Timekeeping, Key Scan and I/O Controller 
Arithmetic Controller 
Master Controller 
On-board Read Only Memory
On-board Read/Write Memory
Plug-in Memories which may be either Read Only Memory or Read/Write Memory
Cascadable Display Drivers 
SN77203 Display Interface Voltage Controller Chip

TI-88J_PCB2.jpg (64318 Byte)The inside view gives you some chip numbers: CD2901, CD2902, CD5402 and TP0531. They are not yet discovered. The CD2901 and CD2902 are called TP0485, the CD5402 is called TP0532 in some documentation. The Schematics Diagram from the Patent application omits the chip numbers.

Running Mike Sebastian's "Calculator forensics"  gives a result of 9.000000955917. It took 7 years before  with the TI-68 another Texas Instruments calculator achieved a similar precision.

TI-88_BP.jpg (20115 Byte)We assume that all Integrated Circuits were manufactured in a low-power C-MOS process, nevertheless used Texas Instruments once again a rechargeable battery pack. Instead of the 3 AA-sized NiCd cells of the TI-59 introduced on 1977 used this design of 1982 just one AA-sized cell. 

TI-88J_BACK.jpg (129602 Byte)CRAM and CROM Modules

The TI-88 accommodates up to two modules in the rear slots. 
Two different type of modues were planned:

TI-88_CM.jpg (12773 Byte)TI-88_CMC.jpg (17248 Byte)CRAM-Modules as user programmable memory with either 1184 program steps or 148 user memories.

With 0, 1 or 2 CRAM-Modules you get a total of:

CRAM-Modules Default Max. Program steps Max. User memory
  Program steps User memory Program steps User memory Program steps User memory
0 480 60 960 0 0 120
1 480 208 2144 0 0 268
2 480 356 3328 0 0 416

TI-88_ML01.jpg (13679 Byte)TI-88_ML01C.jpg (13368 Byte)CROM-Modules as pre-programmed software like the earlier TI-58C/TI-59 Solid State Software™ modules with 15000 program steps.
   Eight modules were already defined in the sales brochures:

CROM-Module Content
1 Master Library
2 Statistics Library
3 Electrical Engineering Library
4 Finance Library
5 Surveying Library
6 Mathematics Library
7 PGM Development Library
8 Chemical Engineering Library

Lucky Numbers?

People in China traditionally associate luck with numbers. As a rule in day-to-day life in China, it is customary to regard even numbers as being more auspicious than odd numbers. Eight, 'Ba' in Chinese has a similar sound to 'Fa', which means to make a fortune. All business men favor this number very much. However, for Texas Instruments the "8" in the type designation was not always a fortune.

We remember some very unlucky calculators:

Calculator Introduction
TI-18 1982 A BASIC calculator with a SCIENTIFIC appeal
TI-38 1979 The odd sibling of the TI-50 and TI-53
TI-68 1989 How NOT to do a keyboard layout
TI-78 1990 Too late? Too advanced? Who knows... 
TI-88 (1982) Killed by competition?
TI-98 (2002) Just a fantasy number, but it would fit.

History repeats - don't miss the story about the PET Project!

The TI-88 is featured in the Texas Instruments Announcement dated May 1982.

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© Joerg Woerner, May 11, 2007. No reprints without written permission.