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. 18, 2000
Filed:
Nov. 01, 1999
John Robert McDonald, Livonia, MI (US);
John Lowell Zeller, Farmington Hills, MI (US);
Thomas Scott Gee, Canton, MI (US);
Ford Global Technologies, Inc., Dearborn, MI (US);
Abstract
An automobile has an electronic device with a nonvolatile memory implementation. The electronic device includes non-programmable nonvolatile memory (ROM), volatile memory (RAM) and programmable nonvolatile memory (EEPROM). A controller (CPU) is coupled to and controls reads and writes to and from the ROM, RAM, and EEPROM. When the CPU detects a key-off event it calculates an error recovery code (checksum) for a data string stored in the RAM and stores the checksum and data into one of two memory locations in the EEPROM. The CPU will alternate between the two memory locations each cycle. When the CPU detects a key-on event it calculates the checksum for the data string stored in the RAM. If the data string is invalid or if validity of the EEPROM data cannot be confirmed, then the CPU copies a predetermined data string from the ROM to the RAM. If the CPU determines that the calculated KAM checksum does not equal the stored KAM checksum, then the CPU copies the EEPROM data string to the KAM. Otherwise, the RAM data string remains untouched.