Texas Instruments TI-59

Date of introduction:  May 24, 1977 Display technology:  LED-stick
New price:  $299.95 (SRP 1977), £249.95
 $180.00 (October 1981)
Display size:  10 (8 + 2)
Size:  6.4" x 3.2" x 1.5"
 162 x 81 x 37 mm3
Weight:  8.5 ounces, 240 grams Serial No:  2422430
Batteries:  BP1A Date of manufacture:  wk 29 year 1980
AC-Adapter:  AC9131 or DC9105 Origin of manufacture:  Netherlands
Precision:  13 Integrated circuits:  TMC0501E, TMC0582, TMC0583, TMC0571, TMC0594, 4*TMC0598
Logic:  AOS - 8 Pending Operations, 9 ()    
Memories:  0-100    
Program steps:  960-160 Courtesy of:  Joerg Woerner
Download leaflet: (US: 3.9M Bytes) Download manual: (US: 21.4M Bytes) 

Introduced together with the TI-58 these calculators introduced a novelty, the Solid State Software Modules™ with up to 5000 program steps. On the backside of the TI-58/59 you'll notice a small lid with a place for a module. The Master Library with 25 different programs was included, a lot of other modules were available.

Don't miss the even greater program collection for the TI-59 resulting from the Professional Program Exchange (PPX-59) initiative started in November 1977.

It took just a few month before Reynolds and Reynolds, headquartered in Dayton, Ohio, introduced in October 1977 with the COMPEG 2001 payroll computing system the first application programmed in a customized Solid State Software Module™. Various application specific modules were developed for the TI-58 and TI-59, based on the "ROM-Code" numbers found in some of the modules we estimate more than 50 different designs. Don't miss the rare and innovative Franken-Calculator Data Dimensioner.

TI-59_PCB.jpg (188855 Byte)Compared with the SR-52 the memory space was raised by a factor of four, sporting up to 100 memories or 960 program steps. A new flexible approach allowed the conversion of one data memory location to eight program steps, base configuration was 60 memories and 480 program steps. Read more about your first steps of programming this calculator here

A similar calculator was sold with the huge desktop-model SR-60A. Don't miss the odd TI-5230.

The TI-59 Programmable calculator marked the end of a calculator evolution started with the SR-50 three years ago. The SR-50 introduced in January 1974 was the first product based on the TMS0500 Building Blocks for Scientific and Programmable Calculators using just the TMC0501 Arithmetic Chip and one TMC0520 SCOM (Scanning and Read Only Memory) Chip for 1k*13 Bits Instruction Memory. The TI-59 Programmable calculator makes full use of the TMS0500 Building Blocks and a closer look at the PCB (printed circuit board) of the TI-59 reveals a total of nine PMOS (P-channel Metal–oxide Semiconductor) chips:

TMC0501E: Enhanced Arithmetic Chip – Register Processor with five 16-digit Registers and segment decoder/driver
TMC0582, TMC0583: TMC0580 Double Scanning and Read Only Memory Chip – 2.5k*13 Bits Instruction Memory with serial interface to Arithmetic Chip, 32 Constants with 16 digits, eight 16-digit Registers and 16-digit display scanning, each
TMC0571: TMC0560 Bare Read Only Memory Chips – 1k*13 Bits Instruction Memory with serial interface to Arithmetic Chip for a combined 6k*13 Bits Instruction Memory
TMC0594: Magnetic I/O Chip – Four channel interface for magnetic card reader to save and load programs with up to 480 steps
TMC0598*4: Four Multi-Register Chips – 240*8 Bits Random Access Memory with 4-bit I/O Bus to Arithmetic Chip, stores 240 program steps or 30 numbers of 16 digits, each

TI-59_C1.jpg (160762 Byte)TI-59_C0.jpg (80174 Byte)Fellow collector Sipke de Wal († May 13, 2004) created a block diagram of the TI-59 calculator and a very detailed diagram of the TMC0501 centered architecture.

If you are interested in the calculating accuracy of scientific calculators don't miss the Calculator forensics.

Comparing the Constant ROM Content with the programmed constants frequently used with computing algorithm of trigonometric functions like sine, cosine, or tangent of an SR-50 manufactured in May 1974 still using the original TMC0521-2 SCOM Chip with the TMC0582 DSCOM Chip of the featured TI-59 with our TMS0500 Platform after recording their ROM Images showed no differences.

Looking into the Key Codes programmed into the second half of the TMC0581 and the complete TMC0582 and comparing with the Source Code from Texas Instruments' US Patent Application #4,153,937 ("A microprocessor system with higher order capabilities provided with two non-volatile memories which are read-only memories in the disclosed embodiment... for use as an electronic calculator") showed no differences. We didn't fully compare the Instruction ROM Content distributed over the two TMC0580 SCOM and one TMC0560 BROM Chips of the featured TI-59 manufactured in May 1979 with the above mentioned US Patent but a few samples revealed no differences.

The TI-59 uses a card reader for magnetic strips, unfortunately they were neither compatible to the SR-52 nor was the drive reliable. Fellow calculator collector Marek Czeszek prepared wonderful Step-by Step Instructions how to clean a TI-59 and repair the card reader. Interested in other calculators with a magnetic card reader? Don't miss the Casio PRO fx-1.

Both TI-58 and TI-59 sport the connector to the printing cradle, these calculators work on the PC-100A, PC-100B and PC-100C revision.

American Micro Products introduced with the Module Selector a very interesting product fitting into the charging bay of the printing cradles.

The calculator was available till the year 1983.

Don't miss the TI-1750 introduced only few weeks before the TI-59, the first LCD-calculator sold by Texas Instruments.

The TI-59 was mentioned in TI's press release dated August 15, 2002 to celebrate the 35th anniversary of its invention of the electronic calculator.

Andreas Gerlich scanned recently the German documentation of the TI-59, please visit his website. Thanks!

Emulating a TI-58/59

If you don't own a TI-58/59 calculator - emulate it!

The TI-59 is featured in the Texas Instruments Incorporated bulletins CB-276, CL-283 and CL-276A dated 1977 resp. 1979.

Find here an excerpt from the Texas Instruments Incorporated leaflet CL-199J dated 1981:

TI Programmable 59

Magnetic card programmable calculator with plug in Solid State Software* and magnetic card storage for business, science, engineering.

Up to 960 program steps, or up to 100 memories. When integrated with any of the libraries it delivers up to 5000 program steps.
Master Library module simply plugs in. Includes 25 different programs in key areas: Math. Statistics. Finance. Blank magnetic cards let you write and record custom programs which may be run individually or integrated with programs in the library modules.
4 types of display testing with an independent test or "t" register.
Up to 10 additional test registers: Loop. Increment. Decrement.
Up to 10 user flags available: Set. Reset. Test.
72 useful labels.
Up to 6 levels of subroutines.
Flexible addressing: Program Steps: Absolute. Indirect. Label. Data Memories: Direct. Indirect.
Complete program editing: Insert. Delete. Single step. Back-step. No Operation.
10 user defined label keys.
Up to 9 sets of parentheses for up to 8 pending operations.
Over 175 functions and operations in sciences and statistics.
Operates with PC-100C.
AC adapter/charger included.
Personal Programming takes you through each function, each operation – step by step. With illustrated examples that will be highly adaptable to work you do: Bond cost. Spherical coordinates. Investments. Quadratic equations.

* Registered Trademark of Texas Instruments Incorporated

© Texas Instruments, 1981


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© Joerg Woerner, December 5, 2001. No reprints without written permission.