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:
Jun. 25, 1991
Filed:
Mar. 17, 1989
Gerald S Pepera, Mentor, OH (US);
Richard S Gunsaulus, Solon, OH (US);
Allen-Bradley Company, Inc., Milwaukee, WI (US);
Abstract
A method and a circuit limit access to a locked portion of memory to periods when application program instructions in the locked portion of memory are being executed. An UNLOCK routine of processor instructions is executed before accessing the portion of the memory storing the application program instructions and a LOCK routine of processor instructions is executed to re-secure the memory after such access. The locking and unlocking is accomplished by addressing a comparator and transmitting data representing either a lock value or an unlock value. The comparator is connected to enable and disable decoding circuitry which in turn controls access to the locked portion of memory.