Nova Patents
US3859635A

Programmable calculator

Abstract

A modular read-write and read-only memory unit capable of employing both direct and indirect decimal and symbolic addressing, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal direct and indirect memory register arithmetic, and an input-output control unit capable of bidirectionally transferring information between the central processing unit and a number of input and output units are controlled by a microprocessor included in the central processing unit. The input and output units include a keyboard input unit with a section capable of being defined by plug-in read-only memory modules and stored programs added by the user, a magnetic card reading and recording unit capable of bidirectionally transferring information between an external magnetic card and the calculator, and a solid state output display unit capable of displaying three lines of numeric information. An output printer unit capable of printing out every alphabetic and numeric character and many other symbols individually and in messages may also be included with the other input and output units.

US3859635A, drawing sheet 1
Sheet 1 of 620

Term

Term ended

Expired 7 January 1992, 34.7 years ago.

  1. Priority and filed
  2. Granted
  3. Expired
  4. Today

17 claims: 1 independent, 16 dependent

  1. 1
    We claim:1. An electronic desk type calculator, portable calculator, or the like including an input unit for entering information into the calculator, a basic first memory unit into which information may be written and from which information may be read, a basic second memory unit for storing routines and/or subroutines to be executed by the calculator in performing selected functions, plug-in adaptor means for enabling the user to removably plug one or more additional second memory units for storing routines and/or subroutines to be executed by the calculator in performing additional selected functions into the calculator to increase the number of functions that may be performed by the calculator, processing means responsive to information from the input unit or the basic first memory unit and to operating states within the calculator itself for selectively executing one or more of the routine and/or subroutines stored in the basic second memory unit to perform one or more of the selected functions employing information from one or both of the input and basic first memory units, said processing means being further responsive to information from the input unit or the basic first memory unit and to operating states within the calculator itself when an additional second memory unit is plugged into the calculator for selectively executing one or more of the routines and/or subroutines stored in that additional second memory unit to perform one or more of the additional selected functions employing information from one or both of the input and basic first memory units, and an output unit for providing an output indication of the results of the selected and additional selected functions performed by the calculator.