Product number (P/N): TMS1802NC,
Keywords/Tags: TMS1802NC
Date of intro-: sep-1971, TimeKeeper IC's (sorted by Year): (Link),
Classification: / Part / Calculator-Chip,
Featuring: Logic-technology: VLSI (Very Large Scale Integration), calculator-on-a-Chip,
Info: First Calculator-on-a-Chip from TEXAS INSTRUMENTS
This TMS1802NC is one of the most significant integrated circuits in the early history of microelectronics.
Introduced in September 1971, it was among the world's first calculator-on-a-chip devices.
While earlier electronic calculators required multiple integrated circuits,
the TMS1802NC consolidated nearly all of the required logic onto a single MOS chip.
The integrated several essential functions into one chip:
A simple CPU,
ROM containing the calculator program,
RAM for temporary data storage,
Keyboard scanning logic,
Display control circuitry.
This high level of integration dramatically reduced the size, cost, and power consumption of electronic calculators, making portable calculators commercially practical.
Rather than being a general-purpose CPU, the TMS1802NC was a highly specialized integrated circuit designed exclusively for calculator applications.
Different calculator models could use customized ROM masks containing different firmware.

Internet: Link-1: DATAMATH CALCULATOR MUSEUM, Link-2: VINTAGE CALCULATORS WEB MUSEUM
Used in: ADVANCE ELECTRONIC: WIRELESS WORLD Desk Calculator, DIGITRON_parts(E): db800/2 (PCB), ELDORADO ELECTRODATA: 8C, SINCLAIR: Executive (version-1), TEXET: 1