Programmable calculator
US4455618A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1981 |
| Grant date | Jun 19, 1984 |
| Priority date | — |
| Expiry date | Feb 20, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F15/02
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A programmable calculator employs modular read-write and read-only memories separately expandable to provide additional program and data storage functions within the calculator oriented toward the environment of the user and two sixteen bit LSI NMOS central processing units. One of the central processing units (LPU) is employed to perform language syntaxing, arithmetic, and general supervision of program execution. The second central processing unit (PPU) is employed for managing input/output operations. Communication between the two central processing units is accomplished by an arrangement through which the two central processing units share a common portion of memory. The calculator also includes a keyboard having a full complement of alphanumeric keys for entering programs and data into the calculator and for otherwise allowing the user to control operation of the calculator. The keyboard further includes a plurality of user-definable keys, some of which are pre-defined to have certain definitions at the time operating power is applied to the calculator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.