DATAMATH CALCULATOR MUSEUM
Texas Instruments introduced the TMC0980 family of single-chip calculator circuits in June 1976 with the two scientific calculators SR-40/TI-30 and the counterpart Business Analyst for financial applications. Within two years Texas Instruments introduced with the TI-50, TI-53, and Business Analyst II calculators with a similar feature set in a much smaller housing and powered by two small button style alkaline batteries good for more than 1,000 hours of operation time. This tremendous progress was made possible by replacing the power-hungry LED Display with an LC-Display and switching the manufacturing process of the single-chip calculator circuit from a 9V metal gate PMOS process to a 3V metal gate CMOS process. The TP0320 family is based on the TMC0980 design, an extension of the TMS1000 Microcomputer family, but sports a larger data memory. The TP0320 chip includes 18,432 Bits Read-only Memory (ROM, 2k*9 Bits) and 832 Bits Read-access Memory (RAM, 12 Registers * 16 digits, 64 Bits Display), a 4-bit Arithmetic unit, a programmable PLA for segment decoding and both segment and digit multiplexing for a 9-digit LC-Display with up to 66 segments and 3 common scan lines.
Driven to keep the die size of the TP0455 as small as possible while adding new features like timekeeping capabilities and a larger display latch to accommodate LC-Displays with up to 12 digits and both ROM and RAM size the main contributors to the die area, Texas Instruments decided to reduce the RAM size of twelve 16-digit Registers of the TP0320 to only eight Registers and added in lieu of it a 4-bit I/O bus for processor-to-processor communication similar to the failed TP0485 to create Master-Slave architectures using two TP0455 chips and effectively doubling ROM and RAM capacity
The TP0458 introduced in 1986 increased the memory capacity of the TP0456 by 50% to 27,648 Bits Read-only Memory (ROM, 3k*9 Bits) and 768 Bits Read-access Memory (RAM, 12 Registers * 16 digits, allowing for very capable programmable calculators with up to 100 program steps like the TI-62 Galaxy, TI-65 and TI-60 in a Master-Slave architecture. With the TI-30 Galaxy and TI-10 Galaxy/Galaxy Junior only two calculators make use of the TP0458 in a single-chip configuration.
The TP0458 was the last single-chip calculator circuit family manufactured in TI’s metal gate CMOS process, subsequent designs made use of Toshiba’s polysilicon gate CMOS process allowing for operation with solar cells and/or a single 1.5 Volts battery.
Learn more about Texas Instruments’ adventure with their own polysilicon gate CMOS process and the ambitious "LCD III Project" leaving behind the failed series
The TP0458 chip includes 27,648 Bits Read-only Memory (ROM, 3k*9 Bits) and 832 Bits Read-access Memory (RAM, 12 Registers * 16 digits, 64 Bits Display), a 4-bit Arithmetic unit, a programmable PLA for segment decoding and both segment and digit multiplexing for a 12-digit LC-Display with up to 84 segments and 4 common scan lines. Both chips can work either in a single-chip architecture or in a dual-chip Master-Slave architecture.
The TP0455/TP0456 and its big brother TP0458 with an increased ROM and RAM capacity were very successful and many designs made use of their flexibility with both programmable ROM and segment decoder.
|TP0458/CD4805||TI-65||Scientific, 100 steps, Timer||Dual chip, Slave - CD4806|
|TP0458/CD4806||TI-65||Scientific, 100 steps, Timer||Dual chip, Master - CD4805|
|TP0458/CD4808||TI-30 Galaxy, Handy Tech Galixa Speech||Scientific||Single chip|
|TP0458/CD4810||TI-62 Galaxy||Scientific, 100 steps||Dual chip, Master - CD4811|
|TP0458/CD4811||TI-62 Galaxy||Scientific, 100 steps||Dual chip, Slave - CD4810|
|TP0458/CD4815||TI-60||Scientific, 84 steps||Dual chip, Master - CD4614|
|TP0458/CD4816||Galaxy Junior, TI-10 Galaxy||Educational||Single chip|
|Architecture||Single-chip Calculator||Scientific, Financial|
|Category||Digit Processor||4-bit digits|
|Related||TP0456||Smaller ROM and RAM|
|ROM Size||27,648 Bits||3072 Words * 9 Bits|
|RAM Size||832 Bits||12 Registers * 16 digits
64 Bits Display Register
|Outputs||4 Common, 21 Segments||Integrated Common Scan Line and Segment Drivers|
|Inputs||5 Keyboard, CPU-CPU communication||Segment to Keyboard Scan-Matrix|
The TP0458 is manufactured in a 5 um metal gate CMOS process.
The die size of the TP0458 is approximately 165 mils * 245 mils / 4.2 mm * 6.2 mm.
The TP0458 uses a 0.6” wide 40-pin SPDIP (Shrink Plastic Dual In-line Package with a 0.07” / 1.778 mm lead pitch).
TP0458/CD4815 (TI-60 Master)
|1||n.c.||40||O||LCD COM 1|
|2||I||Key input 1||39||O||LCD COM 2|
|3||O||Key row 7, M3DP, M2C, M2F, M2G||38||O||Segments|
|4||O||Key row 6, M2D, M2E, M2A, M2B||37||O||Segments STAT, DEG, GRAD, RAD|
|5||I||Key input 1||36||O||Segments MSIGN, M8E, M8F, M8G|
|6||O||Key row 4, M2DP, M1C, M1F, M1G||35||O||Segments M8D, M8C, M8A, M8B|
|7||O||Key row 5, M1D, M1E, M1A, M1G||34||O||Segments M8DP, M7E, M7F, M7G|
|8||I||Key input 1||33||I||Segments M7D, M7C, M7A, M7B|
|9||O||Key row 1, ESIGN, E2E, E2F, E2G||32||O||Segments M7DP, M6E, M6F, M6G|
|10||O||Key row 2, E2D, E2C, E2A, E2B||31||O||Segments M6D, M6C, M6A, M6B|
|11||IO||TP0456/CD4555||30||O||Segments M6DP, M5C, M5F, M5G|
|12||IO||TP0456/CD4555||29||O||Segments M5D, M5E, M5A, M5B|
|13||I||Key input 1||28||O||Segments M5DP, M4C, M4F, M4G|
|14||O||Key row 3, PROG, E1E, E1F, E1G||27||O||Segments M4D, M4E, M4A, M4B|
|15||O||Key row 8, E1D, E1C, E1A, E1B||26||n.c.|
|16||I||Key input 1||25||n.c.|
|17||V||Negative Voltage VSS||24||n.c.|
|18||V||Positive Voltage VDD||23||n.c.|
|19||O||LCD COM 4||22||O||Segments M4DP, M3C, M3F, M3G|
|20||O||LCD COM 3||21||O||Segments M3D, M3E, M3A, M3B|
|The Segment drivers A-G and the Decimal point are connected to a display in the pictured way.|
The keyboards of all calculators based on the TP0458 family consist of an x/y-matrix connected to up to eight segment outputs with the top row ([ON] key) connected to VDD and the keymatrix inputs K1, K2, K3, K4, and K5. Keyboards with nine rows have the top row ([ON] key) connected only to VDD.
Example for the TI-60 with TP458/CD4815:
Calculators based on the TP0458 make use of a 12-digit LCD-display with 4 COM (common scan) lines.
If you have additions to the above datasheet please email: firstname.lastname@example.org.
© Sean Riddle and Joerg Woerner, January 28, 2021. No reprints
without written permission.