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:
Feb. 14, 1989
Filed:
Oct. 16, 1985
Paul C Kroll, New Milford, CT (US);
Sung S Chang, Stamford, CT (US);
Pitney Bowes Inc., Stamford, CT (US);
Abstract
A system for the nonvolatile storage of data, such as a postage meter system, includes a microcomputer coupled to an MNOS type nonvolatile memory and also coupled to an EEPROM type nonvolatile memory, each memory having address lines and data lines. The address lines and data lines of the two nonvolatile memories are coupled to microcomputer ports such that the MNOS memory data lines are always at a high value whenever the EEPROM memory is addressed for the purpose of either writing or reading. The EEPROM nonvolatile memory control terminals and the MNOS nonvolatile memory control terminals are coupled to different ports of the microcomputer. Access to the MNOS nonvolatile memory is achieved by input/output mapping techniques. Access to the EEPROM nonvolatile memory is achieved by memory mapping techniques. In this way, protection is provided against inadvertently accessing the wrong memory or wrong address while executing read/write instructions to a selected memory.