DATAMATH CALCULATOR MUSEUM
With the TMS1802NC Texas Instruments announced on September 17, 1971 the first available standard calculator building block on a chip, it was later renamed into TMS0102. The chip integrates 3520-bit Read-Only program memory, a 182-bit Serial-Access memory 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.
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.
While the TMS0600 architecture was based on the flexible design concept of the TMS0100 architecture with both programmable PLA and ROM techniques, only few design variations appeared. The first two designs of the small TMS0600 family labeled TMS0601 and TMS0602 where just algorithm enhancements of existing designs labeled TMS0119 and TMS0120, respectively:
|[+] [−] [×] [÷]
|[+/−]||[C] [CE]||[CONST]||[F/2/4]||[%]||[Memory]||[EE]||[1/x]||[x2]||[sqr X]||[pi]||Display |
|TMC0605||Canon LE-81M||[+][-][=]||1/2||8||Float||NONE||[sqr X][%±]
|CK||100||250||400||kHz||Level between VSS and VGG|
The TMS0600 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 TMS0600 is approximately 225 mils * 215 mils / 5.8 mm * 5.5 mm.
|1||I||Clock Input||28||V||Common Voltage|
|2||I||Keymatrix input P||27||I||Keymatrix input Q|
|3||O||Digit driver 1 (EXP LSD)||26||I||Keymatrix input N|
|4||O||Digit driver 2 (EXP MSD)||25||I||Keymatrix input O|
|5||O||Digit driver 3 (LSD)||24||O||Segment driver DP|
|6||O||Digit driver 4||23||O||Segment driver H/G (EXP)|
|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||19||O||Segment driver D|
|11||O||Digit driver 9||18||O||Segment driver C|
|12||O||Digit driver 10 (MSD)||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 Segment drivers A-G/H and DP (Decimal Point) are connected to the display in the pictured way. The TMS0602 repurposes the Segment H for the minus sign of the Exponent in the pictured way.|
The keyboards of all calculators based on the TMS0600 family consist of a x/y-matrix connected to the digit driver outputs D1-D11 and the keymatrix inputs KN (Numbers), KO (Operations), KP (Extended Functions), and KQ (Extended Memory 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
Calculators based on the TMS0600 make use of a 9-digit or 12-digit LED (Light-Emitting-Diode) Display with common cathode architecture.
If you have additions to the above datasheet please email: firstname.lastname@example.org.
© Joerg Woerner, December 18, 2021. No reprints
without written permission.