Inventors:
Chris J. Christopher - Loveland CO
Fred W. Wenninger - Loveland CO
Donald E. Morris - Loveland CO
Wayne F. Covington - Loveland CO
Jerry B. Folsom - Loveland CO
Joseph W. Beyers - Loveland CO
John H. Nairn - Longmont CO
Jeffrey C. Osborne - Longmont CO
Assignee:
Hewlett-Packard Company - Palo Alto CA
International Classification:
G06F 302
G06F 918
Abstract:
An adaptable 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 an LSI NMOS central processing unit, capable of handling sixteen-bit parallel binary operations, binary-coded-decimal arithmetic, sixteen-bit parallel input/output operations, two-level interrupt from up to sixteen input/output devices, and a direct memory access channel. The input/output units include a keyboard input unit having a full complement of alphanumeric keys, a magnetic tape cassette reading and recording unit capable of bidirectionally transferring programs and data between the calculator and a magnetic tape, a 32-character solid state output display unit capable of displaying every alphabetic and numeric character and many other symbols individually or in combination, and a sixteen-column alphanumeric thermal printer for printing results of computations, program listings, messages generated by the user and the calculator itself, and error conditions encountered during use of the calculator. All of these input/output units are included within the calculator itself. Many other external input/output units may be employed with the calculator.