Programmable calculator including multifunction keys

• US 4,178,633 A
• Filed: 06/01/1977
• Issued: 12/11/1979
• Est. Priority Date: 12/27/1971
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Watson, Robert E., James, Rex L., Yockey, Francis J., Wenninger, Fred Jr., Olander, Emil E. Jr., Walden, Jack M., Russell, Homer C., Larson, Ivar W., Covington, Wayne F.
• Primary Examiner(s): Malzahn, David H.
• Application Number:
  US05/802,323
• Time in Patent Office: 923 Days
• Field of Search: 364/709
• US Class Current: 708/145
• CPC Class Codes: G06F 11/3636 by tracing the execution of the program
• CPC Class Codes: G06F 15/02 manually operated with input through keyboard and computation using a built-in program, e.g. pocket calculators
• CPC Class Codes: G06F 15/0233 with printing provisions

Abstract

An adaptable programmable calculator is provided by employing modular read-write and read-only memory units capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit. The input and output units include a keyboard input unit having a plurality of alphabetic, numeric, and funtion keys for entering alphameric information, including algebraic statements, into the calculator, a magnetic card reading and recording unit capable of bidirectionally transferring information between an external magnetic card and the calculator, a solid state display unit capable of displaying every alphabetic and numeric character and many other symbols individually and in a line of one or more alphameric statements, and a printer unit capable of printing on thermally sensitive paper every alphabetic and numeric character and many other symbols individually and in alphameric statements or messages. At least one of the function keys of the keyboard input unit is a dual function key. One of the dual functions is selected by actuating the key once, and the other one of the dual functions is selected by actuating the key twice.

Claims

1. An electronic calculator comprising:

keyboard input means including a plurality of alphabetic, numeric, and function keys for entering alphameric information, including algebraic statements, into the calculator, at least one of said function keys representing a plurality of different predetermined functions, each of said plurality of different predetermined functions being designated by a predetermined different number of successive actuations of said one or more of said function keys;

memory means, coupled to said keyboard input means, for storing alphameric information entered into the calculator from said keyboard input means;

processing means, coupled to said keyboard input means and memory means, for processing alphameric information entered into the calculator and stored in said memory means to perform selected functions and to compute the results of selected algebraic statements; and

output means, coupled to said processing means, for providing a visual indication of selected alphameric information;

said processing means including logic means responsive to a particular number of successive actuations of one of said one or more of said function keys for causing entry of the one of said different predetermined functions associated therewith that has been designated by the particular number of successive actuations of that key, said processing means thereafter being operative for performing the entered function designated by the particular number of successive actuations of that key without at the same time performing any of the other predetermined functions represented by that key.

2. An electronic calculator as in claim 1 wherein:

said memory means stores a plurality of flag variables, each of which is associated with a predetermined numeric designator;

one of said function keys comprises a flag control key that represents both flag setting and flag clearing functions;

said logic means is responsive to a single actuation of said flag control key followed by actuation of selected numeric keys designating one of said plurality of flag variables for entering a flag setting function, said logic means being responsive to two succesive actuations of said flag control key followed by actuation of selected numeric keys designating one of said plurality of flag variables for entering a flag clearing function; and

said processing means is operative for performing the entered one of said flag setting and flag clearing functions on the designated flag variable.