Texas Instruments TMS0100 Family


Texas Instruments announced on September 17, 1971 with the TMS1802NC the first available standard calculator building block on a chip, it was later renamed into TMS0102. The chip integrates 3,520 Bits Read-Only program Memory (ROM, 320 Words x 11 Bits), a 182-bit Serial-Access Memory (SAM, 3 Registers * 13 Digits, 2 * 13 Bit-Flags) and a decimal arithmetic logic unit as well as control, timing, and output decoders but no drivers for the display. These function blocks of the chip add up to an overall complexity of roughly 5,000 transistors.

Due to a flexible design concept of the TMS0100 architecture with both programmable PLA and ROM techniques a lot of design variations appeared. These include two different types of the key-matrix, 8 or 10 digits of 7- or 8-segmented outputs. The polarity of the segment output can be programmed. Some displays such as LCD (Liquid-Crystal-Display) are easier to interface with inverted polarity. The blanking of the segments is also programmable within limits to facilitate the interface with certain displays such as Panaplex™. Even the style of the numbers 6, 7 and 9 varied among the family members. While the TMS0100 chip itself provides up to 10 segment outputs for Nixie tube style displays, is the 28-pin package of the device limited to a maximum of 8-segmented outputs.

A typical calculator built around the TMS0100 family performs the four basic functions +, −, ×, and ÷ with either Constant or Chain operation. The calculations are done on a floating decimal-point operation but the display of the results could be selected between the floating-point or a fixed-point format. The keyboard scanning, debouncing and encoding in performed inside the chip. The display outputs are fully decoded with a leading-zero suppression and multiplexed. The TMS0120 could be called the first single-chip scientific calculator circuit, it uses in the SR-10 "slide Rule" calculator SR-10 "Slide Rule" calculator a novel approach to add to the 8-digit Mantissa in scientific notation a 2-digit Exponent and repurposing the unused Segment H for the minus sign of the Exponent.

The related TMS1875 uses a modified leading-zero suppression to output "half-zeros" instead of blanking the corresponding digits, enabling the use of early SP-700 Series planar neon gas discharge displays.

Gordon Moore, the co-founder of Fairchild Semiconductor and Intel predicted already in 1965 that the numbers of transistors in Large-scale Integration (LSI) chips would double every year for the next 10 years. In 1975, looking forward to the next decade, he revised the forecast to doubling every two years, a compound annual growth rate (CAGR) of 41%. While Moore did not use empirical evidence in forecasting that the historical trend would continue, his prediction held since 1975 and has since become known as a "law". Main enablers were and are a combination of both reducing the size of the individual components (process shrink) and increasing the chip size (yield improvement). The manufacturing costs of an Integrated Circuit (IC) are calculated with:

IC cost = (Die cost + Testing cost + Packaging cost) / Final test yield

With the die cost roughly proportional to the die area, testing and packaging costs roughly proportional to the pin count, and the final test yield mostly inverse proportional to the die area, goals are well defined: Keep the die size as small as possible for a set of requirements agreed on. With both ROM (Read-Only Memory) and RWM (Read-Write Memory) sizes the main contributors to the die area of a single-chip calculator circuit and shift-register based data memory (SAM, Serial-Access Memory) of Register Processors denser than RAM (Random-Access Memory) of Digit Processors, Texas Instruments expanded the TMS0100 family two years after its introduction into three different branches:

TMS0600: Increased ROM (384 Words x 11 Bits), Identical SAM (13 Digits Registers), external display drivers. Process shrink, higher functionality
TMS0700: Identical ROM (320 Words x 11 Bits), Identical SAM (13 Digits Registers), external display drivers. Process shrink, identical functionality, cost reduction of IC
TMS0800: Identical ROM (320 Words x 11 Bits), Reduced SAM (11 Digits Registers), integrated segment drivers. Process shrink, reduced functionality, higher integration

Please notice that the members of the TMS0700 family were still marketed and marked as TMS0100 but both the die and the bottom of the chip package usually sport a TMS0700 marking.

It took about a year till the first copy of the original design appeared. US based company Mostek introduced the MK5020P December 1972.

The TMS0112 was manufactured in Japan by Toshiba, too.

Family Members and Applications

Type Calculators Keyboard Constant
Digits Fixed DP Rounding Special
Seg. H Entry
TMS1802 Sinclair Executive, Texet I, Wireless World Desktop [+=][−=] 1/2 8 0-7, F 5/4   NONE
S1, S13
TMS0101 Canon Palmtronic LE-80, LE-83 [+][−][=] 1/2 8 0-7, F DOWN   NONE
S1, S13
TMS0102 Columbia II [+=][−=] 1/2 8 0-7, F 5/4   NONE
S1, S13
TMS0103 Bowmar 901B, JCE Mark II, Montgomery Ward P800, P8F [+=][−=] 1/2 8 0-7, F 5/4   NONE
S1, S13
TMS0105 Canon L800, Panasonic JE-801A, Privileg 2000 [+=][−=] 1/2 8 0-7, F 5/4   NONE
S1, S13
TMS0106 TI-3500, Canon L100S, Radio Shack EC-2000 [+=][−=] 1/2 10 0-9, F 3-POS   S1, S13
S1, S13
TMS0107 Bowmar 901D [+=][−=] 1/2 10 0-9, F 3-POS   S1, S13
S1, S13
TMS0109 TI-3000, Montgomery Ward P800, D8F, Radio Shack EC-1000 [+=][−=] 1/2 8 0-7, F 5/4   S1, S13
S1, S13
TMS0110 TI-2500 Pre-series [+][−][=] 2/2 8 0-7, F DOWN   NONE
S1, S13
TMS0111 Minimath Prototype [+][−][=] 2/2 8 0-7, F DOWN Inverted
S1, S13
TMS0112 Toshiba BC-0801B, BC-802B [+=][−=] 1/2 8 0-7, F 3-POS   NONE
S1, S13
TMS0115 Olympia CD80, Panasonic JE-850 [+][−][=] 1/2 8 Float NONE   S1, S13
S1, S13
TMS0117   BCD Coprocessor   10     BCD Output   (Note)        
TMS0118   [+][−][=] 2/2 10 0-9, F 3-POS   S1, S13
S1, S13
TMS0119 TI-2500, Heathkit IC-2108 [+][−][=] 2/2 8 0-7, F DOWN   NONE
S1, S13
TMS0120 SR-10, Montgomery Ward P300, Radio Shack EC-425 [+][−][=]   8+2 Float NONE [EE][1/x]
TMS0121 Olympia CD101, Panasonic JE-1001 [+][−][=] 1/2 10 0-9, F DOWN, 5/4 [X<>Y] NONE
S1, S13

Note 1: The TMS0117 uses a Binary Code Decimal Output on its Segment Outputs SA, SB, SC, and SD
Note 2: Learn more about the MOS Numbering System used by Texas Instruments' early MOS Chips.


  Description Comments
Architecture Single-chip Calculator First Generation
Category Register Processor 44-bit registers (11 digits * 4 Bits)
Related TMS1875
Modified leading-zero suppression
Scientific Notation
Larger ROM
Integrated Segment Drivers
ROM Size 3,520 Bits 320 Words * 11 Bits
RAM Size 182 Bits 3 Registers * 13 Digits,
2 * 13 Bit-Flags
Outputs 11 Digits, 9 Segments External Digit and Segment Drivers
Inputs 4 Keyboard
0 Miscellaneous
Digit to Keyboard Scan-Matrix

DCM-50A Platform Compatibility

The Datamath Calculator Museum DCM-50A (Platform) supports the TMS0100 Product Family with its left-most TMS0100 Textool Test Socket set to DCM-50A (TMS0100) mode. Both Characterization of TMS0100 Calculator Circuits and Reverse-engineering of TMS0100 Calculator Circuits is supported by the DCM-50A (TMS0100).

Technical Specifications

Parameter Min Typ Max Unit Comments
VSS   0   V   
VDD -8.1 -7.2 -6.6 V   
VGG -16.2 -14.4 -13.2 V   
IDD   17 25 mA  
IGG   10 15 mA  
CK  100 250 400 kHz  Level between VSS and VGG       


The original TMS0100 was manufactured in a 10 um metal gate PMOS process (metal width = 0.40 mil / 10 um, metal spacing = 0.40 mil / 10 um, diffusion width = 0.40 mil / 10 um, diffusion spacing = 0.4 mil / 10 um).

The die size of the TMS0100 is approximately 230 mils * 230 mils / 5.9 mm * 5.8 mm.


The TMS0100 uses a standard 0.6” wide 28-pin DIP (Dual In-line Package with a 0.1” / 2.54 mm lead pitch).

Pin Configuration

Pin IO Function Pin IO Function
1 I Clock Input 28 V Common Voltage
2 I Keymatrix input P 27 I Keymatrix input Q
3 O Digit driver 1 (LSD) 26 I Keymatrix input N
4 O Digit driver 2 25 I Keymatrix input O
5 O Digit driver 3 24 O Segment driver DP
6 O Digit driver 4 23 O Segment driver H
7 O Digit driver 5 22 O Segment driver G
8 O Digit driver 6 21 O Segment driver F
9 O Digit driver 7 20 O Segment driver E
10 O Digit driver 8 (MSD8) 19 O Segment driver D
11 O Digit driver 9  18 O Segment driver C
12 O Digit driver 10 (MSD10) 17 O Segment driver B
13 O Digit driver 11 (OVER) 16 O Segment driver A
14 V Negative Voltage VDD 15 V Negative Voltage VGG
The Segment drivers A-G/H and DP (Decimal Point) are connected to the display in the pictured way.

Keyboard Scan-Matrix

The keyboards of all calculators based on the TMS0100 family consist of a x/y-matrix connected to the digit driver outputs D1-D11 and the keymatrix inputs KN (Numbers) and KO (Operations). In the fixed-point output format mode the position of the decimal point is selected with the KP (Decimal Point) input. The Constant/Chain switch is connected between D10-KQ (Constant).

Scanning is performed in D11 → D1 direction at a rate of about 584 Hz:

State Time = 3 Clocks = 0.012 ms @ CK=250 kHz
Digit Time = 13 States (1 Instruction Cycle) = 0.156 ms @ CK=250 kHz
Scan Time = 11 Digit Times (D1 to D11) = 1.712 ms @ CK=250 kHz

TMS0102, 0103, 0105, 0109


TMS0101, 0110

D1 1   DP1   D1 1 + DP1  
D2 2 × DP2   D2 2 × DP2  
D3 3 ÷ DP3   D3 3 ÷ DP3  
D4 4   DP4   D4 4 DP4  
D5 5 += DP5   D5 5   DP5  
D6 6 −= DP6   D6 6   DP6  
D7 7 +/− DP7   D7 7 +/− DP7  
D8 8       D8 8 =    
D9 9 .     D9 9 .    
D10 0 CE DP0  K D10 0 CE DP0  K
D11   C     D11   C    





D1 1   DP1   D1 1   DP1  
D2 2 × DP2   D2 2 × DP2  
D3 3 ÷ DP3   D3 3 ÷ DP3  
D4 4   DP4   D4 4   DP4  
D5 5 += DP5   D5 5 += DP5  
D6 6 −= DP6   D6 6 −= DP6  
D7 7 +/− DP7 5/4 D7 7 +/− DP7 UP
D8 8   DP8   D8 8   DP8  
D9 9 . DP9 DWN D9 9 . DP9 DWN
D10 0 CE DP0 K D10 0 CE DP0 K
D11   C     D11   C    





D1 1 + DP1   D1 9    
D2 2 × DP2   D2 8 +    
D3 3 ÷ DP3   D3 7 ×    
D4 4 DP4   D4 6 ÷ x  
D5 5   DP5   D5 5 CD    
D6 6   DP6   D6 4 EE 1/x  
D7 7 +/− DP7 5/4 D7 3 +/−    
D8 8 = DP8   D8 2 = x2  
D9 9 . DP9 DWN D9 1 .    
D10 0 CE DP0  K D10 0      
D11   C     D11   C    





D1 1 + DP1   D1        
D2 2 × DP2   D2        
D3 3 ÷ DP3   D3        
D4 4 DP4   D4        
D5 5   DP5   D5        
D6 6   DP6   D6        
D7 7 X<>Y DP7   D7        
D8 8 = DP8   D8        
D9 9 . DP9   D9        
D10 0 CE DP0 5/4 D10        
D11   C     D11        


Calculators based on the TMS0100 use all kinds of displays including but not limited to LED (Light-Emitting-Diode), Panaplex™ (Gas-Discharge-Display), low voltage VFD (Vacuum-Fluorescent-Display), and - with the failed Minimath calculator - even LCD (Liquid-Crystal-Display) technology. Texas Instruments introduced together with the calculator chip two pre-configured LED-modules (DIS40, DIS95) based on the TIL360 arrays, the corresponding segment drivers (SN75491) and digit drivers (SN75492) and even the 1KS/6KS Klixon™ keyboard. Most early 8-digit designs made use of these parts.

horizontal rule

If you have additions to the above datasheet please email:

© Sean Riddle and Joerg Woerner, February 02, 2001. No reprints without written permission.