Method and apparatus for storing main data with two checkup data
First Claim
Patent Images
1. An apparatus comprising:
- a backup memory having first, second and third storage areas; and
a microcomputer programmed to calculate a main data and two checkup data, and store the main data and the two checkup data in the first, the second and the third storage areas of the backup memory, respectively,wherein each of the two checkup data has a data length smaller than that of the main data;
the microcomputer stores the main data in the first storage area between storing the two checkup data in the second and the third storage area; and
both of the two checkup data are calculated from the main data so that both of the two checkup data have a predetermined relation to the main data.
1 Assignment
0 Petitions
Accused Products
Abstract
An electronic control unit has a microcomputer and a backup RAM, which stores its data irrespective of ON/OFF of an engine ignition switch. The backup RAM stores a main data in its storage area, and two checkup data in its storage areas, respectively. The two checkup data are calculated as a two-byte data from the main data of a 4-byte floating points type data and equal to each other. The microcomputer executes a data storing operation in the order of one checkup data, the main data and the other checkup data. The microcomputer determines that the main data is correct when either one of the checkup data is determined correct.
13 Citations
13 Claims
-
1. An apparatus comprising:
-
a backup memory having first, second and third storage areas; and a microcomputer programmed to calculate a main data and two checkup data, and store the main data and the two checkup data in the first, the second and the third storage areas of the backup memory, respectively, wherein each of the two checkup data has a data length smaller than that of the main data; the microcomputer stores the main data in the first storage area between storing the two checkup data in the second and the third storage area; and both of the two checkup data are calculated from the main data so that both of the two checkup data have a predetermined relation to the main data. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method comprising steps of:
-
determining a main data; determining first and second checkup data, each of the checkup data has a data length smaller than that of the main data; storing the first checkup data in a first checkup data storage area of a backup memory; storing the main data in a main data storage area of the backup memory after the first checkup data is stored; and storing the second checkup data in a second checkup data storage area of the backup memory after the main data is stored; wherein the first and the second checkup data are determined from the main data so that the first and second data have a predetermined relation to the main data. - View Dependent Claims (8, 9, 10, 11, 12)
-
-
13. A method comprising steps of:
-
determining a main data by a computer mounted in a vehicle; determining first and second checkup data by the computer from the main data to have predetermined first and second relations to the main data so that the first and second checkup data are identical or equivalent to each other; storing the first checkup data in a first checkup data storage area of a backup memory, which is operable even after a power supply to the computer is cut-off; storing the main data in a main data storage area of the backup memory after the first checkup data is stored; and storing the second checkup data in a second checkup data storage area of the backup memory after the main data is stored.
-
Specification