The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 07, 1987
Filed:
Nov. 12, 1985
Michael F Berger, Fort Worth, TX (US);
Sammy D Sawyer, Arlington, TX (US);
Tandy Corporation, Fort Worth, TX (US);
Abstract
A dual processor system in which one processor is dedicated to input/output tasks while the other is dedicated to high level language tasks when operating as a 16-bit machine. The processors include a first microprocessor which is an 8-bit machine, and a second microprocessor which is a 16-bit machine. The first processor has a memory associated therewith which may, for example, be a 64K memory while the second processor has a larger capacity memory. The second processor does not access the memory of the first processor, however, the first processor can access a portion of the second processor's memory. Access to the second processor's memory is controlled by an arbitrator that is operated by system software to prevent access conflicts. For boot-up during power-up operation, a boot ROM is used, attached to the 8-bit processor having stored therein a boot strap program that is initially loaded into the 8-bit processor memory. If the operating system loaded from a diskette indicates 8-bit software, then the 16-bit processor is maintained reset or halted. On the other hand, if the operating system is a 16-bit system, then the boot program loads the 16-bit memory making the 16-bit processor the main processor. The 8-bit processor then functions as an I/O processor. This boot-up procedure allows the 8-bit processor to turn on first and makes the system initially appear as an 8-bit processor system. In this way the system is compatible with software written for an 8-bit machine even though the system is normally run and identified as a 16-bit machine.