Michael Shannon Cochran

US Patent:

H19704, Jun 5, 2001

Filed:

Feb 1, 1990

Appl. No.:

7/473541

Inventors:

Gary W. Boone - Colorado Springs CO
Michael J. Cochran - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G06F 1500

US Classification:

712 32

Abstract:

A variable function calculator utilizes a fixed program memory array such as a programmed read only memory in which a number of programs are stored depending upon the desired functions of the calculator. The calculator also includes a program counter, an instruction register, control decoders, jump-condition circuits, a clock generator, a timing generator, digit and FLAG mask decoders, key input logic, a register and FLAG data storage array, a decimal and FLAG arithmetic logic unit, an output decoder, and a digit scanner which scans both the keyboard and display outputs. Aside from providing basic desk top calculator functions, the read only memory may be programmed so that the system provides metering functions, arithmetic teaching functions, control functions, etc. A preferred embodiment of the invention is capable of being fabricated as a monolithic integrated semiconductor system utilizing contemporary metal-insulator-semiconductor techniques.