Texas Instruments TMS0102 Family


With the TMS0102 Texas Instruments introduced end of the year 1971 the first available standard calculator building block on a chip. The chip contains 3520-bit read-only program memory (320 words x 11 bits), a 182-bit random-access memory (44 x 4 bits, flags) and a decimal arithmetic logic unit as well as control, timing, and output decoders but no drivers for the display. This gives an overall complexity of roughly 5,000 transistors. 

Due to a flexible design concept 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. Even the style of the numbers 4,6 and 9 varied among the family members.

A typical calculator built around the TMS0102 family performs the four basic functions +,-,*,: 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 family was later expanded with the TMS0123 design.

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 produced in Japan by Toshiba, too. 

Family Members and Usage

Type Calculator Key-Matrix Digits Segment decoder Timing
TMS0101 Canon Palmtronic LE-83 [+],[-],[=] 8 LED
TMS0102 Columbia II [+=],[-=] 8 LED
TMS0103 Bowmar 901B, JCE Mark II [+=],[-=] 8 LED
TMS0105 Canon L800 [+=],[-=] 8 LED
TMS0106 TI-3500, Canon L100S [+=],[-=] 10 Panaplex
TMS0107 Bowmar 901D [+=],[-=] 10   LED
TMS0109 TI-3000 [+=],[-=] 8 Panaplex
TMS0110 TI-2500 Preseries  [+],[-],[=] 8   LED
TMS0111 Minimath prototypes  [+],[-],[=] 8   LCD
TMS0112 Toshiba BC-0802 [+=],[-],[=] 8   LED
TMS0115 Panasonic JE-850U [+],[-],[=] 8 LED
TMS0118   [+],[-],[=] 10   LED
TMS0119 TI-2500, Heathkit IC-2108 [+],[-],[=] 8 LED
TMS0719 TI-2500 [+],[-],[=] 8 LED
TMS1875 Heathkit IC-2008 [+],[-],[=] 8 LED


Technical Specification

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


The TMS0102 uses a standard DIP-28 package.

Pin Description

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-H and the Decimal point are connected to a display in the pictured way.

Keyboard Scanmatrix

The keyboards of all calculators based on the TMS0102 family consist of a x/y-matrix connected to the digit driver outputs D1-D11 and the keymatrix inputs KN and KO. In the fixed-point output format mode the position of the decimal point is selcted with the KP input. The Constant/Chain switch is connected between D10-KQ.


[+=],[-=] Type


[+],[-],[=] Type

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    


Calculators based on the TMS0102 use all kinds of displays. 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). Most designs make use of these parts.

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If you have additions to the above datasheet please email:

Joerg Woerner, February 02, 2001. No reprints without written permission.