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Texas Instruments TMS1000 Family

• Features

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. 

The TMS1802NC single-chip calculator circuit was later renamed to TMS0102 and Texas Instruments sold millions and millions of TMS0100 chips to calculator manufacturers like Bowmar, Canon, Hearthkit, and Toshiba and dozens more while using them in their own calculators like TI-2500, TI-3000, and TI-3500, too.

While the U.S. Patent Office ruled that Texas Instruments engineer Gary W. Boone is the inventor of the single-chip microcontroller, didn’t gain the TMS0100 any traction outside of the calculator business. Although the Register Processor architecture of the TMS0100 proved to be very efficient on operands stored in its three shift registers based 13-digit Registers, were digit manipulations rather inefficient and needed to cycle a complete 13-digit word through the ALU while masking twelve of the thirteen digits. Consequently, Texas Instruments introduced in October 1974 with the TMS1000 their first Digit Processor by replacing the 182-bit Serial-Access Memory with a 256-bit Random-Access Memory organized as 64 Digits or the equivalent of 4*16-digit Registers and changing the width of the instructions from 11-bit to 8-bit. The new architecture allowed to access any 4-bit data memory location with the means of a pointer gaining a lot of flexibility in digit manipulations bit losing performance on register operations typically used in electronic calculators.

Despite the fact that TI’s first application of the TMS1001 was the SR-16 scientific calculator, took the TMS1000 family off in other applications from appliances to garage door openers to toys and within a few years annual sales volume was in the tens of millions.

The original TMS1000 chip introduced in October 1974 had similar characteristics as the TMS0100, but later members of the growing product portfolio increased memory capacity, number of output latches, and output driver characteristics:

Chip Series TMS0100 TMS1000 TMS1200 TMS1070 TMS1270 TMS1100 TMS1300 TMS1170 TMS1370 TMS1400 TMS1600 TMS1470 TMS1670 TMS1700
Technology PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS PMOS
Supply Voltage 7.2V, 14.4V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V 15V or 9V
Pins, Package 28 DIP 28 DIP 40 DIP 28 DIP 40 DIP 28 DIP 40 DIP 28 DIP 40 DIP 28 DIP 40 DIP 28 DIP 40 DIP 28 DIP
Instruction ROM
(Words, Bits)
320*13
3,520
1k*8
8,192
1k*8
8,192
1k*8
8,192
1k*8
8,192
2k*8
16,384
2k*8
16,384
2k*8
16,384
2k*8
16,384
4k*8
32,768
4k*8
32,768
4k*8
32,768
4k*8
32,768
512*8
4,096
Data Storage
(Files, Digits, Bits)
3*13 SAM
156+26
4*16 RAM
256
4*16 RAM
256
4*16 RAM
256
4*16 RAM
256
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
8*16 RAM
512
2*16 RAM
128
K Input Lines
(Keyboard Scan)
4 4 4 4 4 4 4 4 4 4 8 4 8 4
R Output Latches
(Digits Scan)
11 11 13 11 13 11 16 11 16 11 16 10 16 9
O Outputs
(Segments)
9
(11 on Die)
8 8 8 10 8 8 8 8 8 8 8 8 8
Output PLA
(Inputs, Outputs
Terms)
5 to 11
18
5 to 8
20
5 to 8
20
5 to 8
20
5 to 10
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
5 to 8
20
Output Drivers
(Display Technology)
None None
LED Level
None
LED Level
VFD VFD None
LED Level
None
LED Level
VFD VFD None
LED Level
None
LED Level
VFD VFD None
LED Level

While the TMS1000 Microcomputer family was wildly successful in non-calculator applications and made its most prominent appearance in the Speak & Spell toy, was the original design used only with three TI calculators.

• Family Members and Applications

Type Calculator Application Comments
TMS1001 SR-16 Scientific First TMS1000 application
TMS1014 TI-5050 Printing With TMS1214
TMS1016 SR-16 II, Zayre Concept III Scientific Successor of SR-16
TMS1000/CD8000 PC-800 Printer With TMS1300/CD8020

 

• Architecture

  Description Comments
Architecture Single-chip Calculator First Generation Digit Processor
Category Digit Processor 44-bit registers (11 digits * 4 Bits)
Related TMS1000 Portfolio Different Memory capacity, # of Inputs and Outputs, Output drivers
ROM Size 8,192 Bits 1,024 Words * 4 Bits
RAM Size 256 Bits 4 Registers * 16 Digits
Outputs 11 Digits, 8 Segments External Digit Drivers
Inputs 4 Keyboard
0 Miscellaneous
Digit to Keyboard Scan-Matrix

• Technical Specifications

Parameter Min Typ Max Unit Comments
VSS   0   V   
VDD -14 -15 -17.5 V Later versions rated for 9V, too
IDD   4.5 10 mA 300 kHz
Ext. CK  100   400 kHz Level between VSS and VDD
Int. CK  250 300 350 kHz Rext= 50 kOhm, Cext= 47 pF

• Technology

The original TMS1000 was manufactured in a 8 um metal gate PMOS process (metal width = 0.30 mil / 8.0 um, metal spacing = 0.35 mil / 9.0 um, diffusion width = 0.25 mil / 6.0 um, diffusion spacing = 0.35 mil / 9.0 um).
The die size of the TMS1000 is approximately 230 mils * 230 mils / 5.8 mm * 5.8 mm.

• Packaging

The TMS1000 uses in TI's calculator applications 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 O R8 Output 28 O R7 Output
2 O R9 Output 27 O R6 Output
3 O R10 Output 26 O R5 Output
4 V Negative Voltage VDD 25 O R4 Output
5 I K1 Input 24 O R3 Output
6 I K2 Input 23 O R2 Output
7 I K4 Input 22 O R1 Output
8 I K8 Input 21 O R0 Output
9 I INIT (Reset) 20 V Common Voltage VSS
10 O O7 Output 19 I OSC2 (Ext. CLK = VSS)
11 O O6 Output  18 I OSC1 (Cext, Rext) or Ext
12 O O5 Output 17 O O0 Output
13 O O4 Output 16 O O1 Output
14 O O3 Output 15 O O2 Output


In a typical calculator application the digits of the display are connected with drivers to the scanning R Outputs, the segments of the display are connected directly or with drivers to the O Outputs making use of the provided 5 to 8 PLA to decode the segments, and the keyboard matrix is connected between the K Inputs and R Outputs.

Example for the SR-16 II:

Pin IO Function Pin IO Function
1 O Digit driver 10 28 O Digit driver 9
2 O Digit driver 11 (M-LSD) 27 O Digit driver 8
3 O Digit driver 3, 12 (OVER) 26 O Digit driver 7
4 V Negative Voltage VDD 25 O Digit driver 6
5 I K1 Input 24 O Digit driver 5
6 I K2 Input 23 O Digit driver 4 (M-LSD)
7 I K4 Input 22 O Digit driver 2 (E-MSD)
8 I K8 Input 21 O Digit driver 1 (E-LSD)
9 I INIT (Reset) 20 V Common Voltage VSS
10 O Segment driver DP 19 I OSC2 (Connected to OSC1)
11 O Segment driver G 18 I OSC1 (100 pF, 30 kOhm)
12 O Segment driver F 17 O Segment driver A
13 O Segment driver E 16 O Segment driver B
14 O Segment driver D 15 O Segment driver C
The Segment drivers A-G and DP (Decimal Point) are connected to the display in the pictured way. 

• Keyboard Scan-Matrix

The keyboards of calculators based on the TMS1000 family consist of a x/y-matrix connected to the R Outputs R0-R10 and the K Outputs K1-K4 allowin for a maximum of 44 switches.

Example for the SR-16 II:

  K1 K2 K2 K4
R0 - D1   C    
R1 - D2     CD 0
R2 - D4       1
R3 - D5     +/- 2
R4 - D6 X2     3
R5 - D7 log   EE 4
R6 - D8 sqrX + . 5
R7 - D9 lnX - STO 6
R8 - D10 1/X * RCL 7
R9 - D11 eX : SUM 8
R10 - D3,12 yX = PI 9

• Display

Calculators based on the TMS1000 use all kinds of displays. Texas Instruments recommends for LED Displays the corresponding segment drivers SN75491 and digit drivers SN75492.

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

© Sean Riddle and Joerg Woerner, January 17, 2021. No reprints without written permission.