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Texas Instruments TMC1980

Features

The TMC0980 family of single-chip calculator circuits was introduced in June 1976 with the two scientific calculators SR-40/TI-30 and the financial calculator Business Analyst of the Majestic product line. The TMC0980 is an extension of the TMS1000 Microcomputer family and allows for highly cost optimized calculators with up to 40 keys and a 9-digit LED Display powered by a 9V battery. Additional cost savings could be achieved by replacing a conventional [ON-OFF] switch with a simple push-button [ON] key. The TMC0980 chip includes 18,432 Bits Read-Only Memory (ROM, 2k*9 Bits) and 576 Bits Random-Access Memory (RAM, 9 Registers * 16 digits), a 4-bit Arithmetic unit, a programmable PLA for segment decoding and both segment and digit drivers for a 9-digit LED Display.

Due to a flexible design concept with both programmable ROM and segment decoder some design variations of the TMC0980 were introduced and Texas Instruments expanded the product family before finally converting the design with the TP0320 from a 9V metal gate PMOS process to a 3V metal gate CMOS process:

TMC1980: 9-digit, 7-segment VF-Display, 28-pin Package (Dataman)
TMC0260: 11-digit, 7-segment VF-Display, Thermal Printer Interface, 40-pin Package (TI-5040)
TMC0270: 9-digit, 14-segment VF-Display, 40-pin Package (Speak & Spell)

The TMC1980 was introduced in June 1977 with the TI-1680 Replay Calculator but made a much more lasting appearance with the Dataman Educational Toy. The TMC1980 replaced the segment and digit drivers for a 9-digit LED Display with high-voltage drivers for a VF-Display and includes both an integrated charge pump driver to generate the high voltage (around -22V) for the Anodes and Grids of the VF-Display and integrated drivers for the Filament (heater) of it.

Family Members and Applications

Type Calculator/Product Application Comments
TMC1981 TI-1680, TI-2550 IV Replay Calculator Uses TMC0999 memory
TMC1982 TI Dataman Educational Single-chip application
TMC1983 TI-45 Scientific Like SR-40 w/ VF-Display
TMC1984 Spelling B Educational TMC0272 Master
TMC1986 Math Marvel Educational Single-chip application

 

Architecture

  Description Comments
Architecture Single-chip Calculator Scientific, Financial
Category Digit Processor 4-bit digits
Related TMC0980
TMC0260
TMC0270
7-segment LED-Display
7-segment VF-Display, Printer
14-segment VF-Display
ROM Size 18,432 Bits 2048 Words * 9 Bits
RAM Size 576 Bits 9 Registers * 16 digits
Outputs 9 Digits, 8 Segments Integrated Digit and Segment Drivers, Filament and Charge pump Drivers
Inputs 5 Keyboard
1 Oscillator Mode
Digit to Keyboard Scan-Matrix

Technical Specifications

Item Min Typ Max Unit Comments
VSS   0   V   
VDD   -9.0   V   
VBIAS   -22.0   V   
CK  250 350 450 kHz  Internal oscillator       

Technology

The TMC1980 was manufactured in a 6 um metal gate PMOS process (metal width = 0.25 mil / 6.0 um, metal spacing = 0.25 mil / 6.0 um, diffusion width = 0.15 mil / 4.0 um, diffusion spacing = 0.30 mil / 8.0 um).

The die size of the TMC1980 is approximately 195 mils * 190 mils / 4.9 mm * 4.8 mm.

Packaging

The TMC1980 uses a 0.4 wide 28-pin SPDIP (Shrink Plastic Dual In-line Package with a 0.07 / 1.778 mm lead pitch).

Pin Configuration

TMC1982 (Dataman)

Pin IO Function Pin IO Function
1 O Digit driver 3 28 O Digit driver 4
2 O Digit driver 2 27 O Digit driver 5
3 O Digit driver 1 (rightmost) 26 O Digit driver 6
4 O Segment driver DP 25 O Digit driver 7
5 O Voltage Tripler Output 24 O Digit driver 8
6 V Negative Voltage VDD 23 O Digit driver 9 (leftmost)
7 I Keymatrix input 1 22 V Display Voltage VBIAS
8 I Keymatrix input 2 21 I Oscillator Mode
9 I Keymatrix input 3 20 V Positive Voltage VSS
10 I Keymatrix input 4 19 O Segment driver G
11 O Filament driver 1 18 O Segment driver B
12 O Filament driver 2 17 O Segment driver C
13 O Segment driver A 16 O Segment driver D
14 O Segment driver F 15 O Segment driver E


TMC1983 (TI-45)

Pin IO Function Pin IO Function
1 O Digit driver 3 28 O Digit driver 4
2 O Digit driver 2 27 O Digit driver 5
3 O Digit driver 1 (rightmost) 26 O Digit driver 6
4 O Segment driver DP 25 O Digit driver 7
5 O Voltage Tripler Output 24 O Digit driver 8
6 V Negative Voltage VDD 23 O Digit driver 9 (leftmost)
7 I Keymatrix input 1 22 V Display Voltage VBIAS
8 I Keymatrix input 2 21 V Positive Voltage VSS
9 I Keymatrix input 3 20 O Segment driver G
10 I Keymatrix input 4 19 O Segment driver B
11 I Keymatrix input 8 18 O Segment driver C
12 O Filament driver 1 17 O Segment driver D
13 O Filament driver 2 16 O Segment driver E
14 O Segment driver A 15 O Segment driver F
The Segment drivers A-G and DP (Decimal Point) are connected to the display in the pictured way. 

Keyboard Scan-Matrix

The keyboards of products based on the TMC1980 family consist of an x/y-matrix connected to up to seven digit outputs with the top row ([ON] key) connected to VSS and the keymatrix inputs K1, K2, K3, K4. The TMC1983 used with the TI-45 has the keymatrix input K8 bonded to a pin but drops the Oscillator Mode input instead. 

Example for the Dataman with TMC1982: 

  K4 K3 K2 K1
VSS Electro Flash [?] OFF ON
Digit 5 Wipe Out Number Guesser Force Out :
Digit 6 7 8 9 *
Digit 7 4 5 6 -
Digit 8 1 2 3 +
Digit 9 GO 0 Memory Bank =


Example for the TI-45 with TMC1983: 

  K2 K4 K1 K8 K3
VSS 1/X X2 sqrX OFF ON
Digit 9 INV sin cos tan DRG
Digit 8 K EE log lnX YX
Digit 7 PI % ( ) :
Digit 6 STO 7 8 9 *
Digit 5 RCL 4 5 6 -
Digit 4 SUM 1 2 3 +
Digit 3 EXC 0 . +/- =

Display

Calculators based on the TMC1980 make use of a 9-digit VF-Display. 

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

Sean Riddle and Joerg Woerner, April 6, 2021. No reprints without written permission.