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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 * 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 Product 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 Product Family two years after its introduction into three different branches:

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

Please notice that the members of the TMS0700 Product 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.

Type

Calculators

Keyboard

Constant (M/D)

Digits

Fixed DP

Rounding

Special Functions

Seg./Dig. Blanking

(6,7,9) Font

Seg. H

Entry Overflow

Calculating Overflow

Pref. Type

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

YES

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

YES

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

YES

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 Segments

NONE 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

YES

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] [x2][√x]

NONE NONE

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	BCD-serial
Related	TMS1875 TMS0120 TMS0600 TMS0700 TMS0800	Modified leading-zero suppression Scientific Notation Larger ROM Die-shrink 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 Drivers External Segment Drivers
Inputs	4 Keyboard 0 Miscellaneous	Digit to Keyboard Scan-Matrix

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

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.

The keyboards of all calculators based on the TMS0100 Product 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
	KN	KO	KP	KQ		KN	KO	KP	KQ
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

	TMS0106					TMS0107
	KN	KO	KP	KQ		KN	KO	KP	KQ
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

	TMS0118					TMS0120
	KN	KO	KP	KQ		KN	KO	KP	KQ
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

	TMS0121
	KN	KO	KP	KQ		KN	KO	KP	KQ
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

• Display

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.

If you have additions to the above datasheet please email: joerg@datamath.org.

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