Programmable calculator including scrolling alphanumeric display means

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, a central processing unit, and an input-output control unit for 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, a magnetic card reading and recording unit, a solid state multi-character display unit capable of displaying every alphabetic and numerical character and many other symbols individually and in a line of one or more alphameric statements, and a thermal printer unit. The keyboard input unit includes a DISPLAY key that permits the user to manually or programmably display the results of an arithmetic expression, an alphameric message, or the contents of any designated data register, either singly or as a string, and without thereby altering the contents of the data register. Mnemonic representations of each key of the keyboard input unit appear in the display and are automatically scrolled to the left of the display as additional keys are actuated. Displayed strings of alphameric characters may be manually scrolled left or right across the display by selective actuation of a pair of display control keys. The display may be cleared independently of any memory registers.