Microcomputer control system in which programs can be modified from outside of the system and newer versions of the modified programs are determined and executed

• US 6,496,978 B1
• Filed: 05/21/1999
• Issued: 12/17/2002
• Est. Priority Date: 11/29/1996
• Status: Expired due to Term

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ito, Tamotsu
• Primary Examiner(s): Morse, Gregory
• Assistant Examiner(s): NGUYEN BA, HOANG VU A
• Application Number:
  US09/308,578
• Time in Patent Office: 1,306 Days
• Field of Search: 717/170, 717/168, 711/102, 711/103, 711/115, 711/154, 711/155, 712/37, 714/719, 714/819
• US Class Current: 717/170
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57
• CPC Class Codes: G06F 8/66 of program code stored in read-only memory [ROM]
• CPC Class Codes: G06F 9/24 Loading of the microprogram

Abstract

Programs or data in a mask ROM incorporated in a one-chip microcomputer can be modified from the outside. With version information appended to each of a mask ROM 2 incorporated in a one-chip microcomputer 6 and an external EPROM 5, by comparing the version numbers, programs (tasks and subroutines) of a new version can always be executed and update data of a new version can be used. The programs can be customized for each user.

Claims

1. A microcomputer control system in which programs incorporated in a microcomputer may be modified based on programs provided from outside of said microcomputer, and wherein version information is appended to each of the programs incorporated in said microcomputer and the programs provided from outside of the microcomputer, said system comprising:

means for using said version information to judge which of the programs incorporated in said microcomputer and the programs provided outside of said microcomputer, is newer; and

means for using whichever programs are newer,

wherein said version information is converted into numeric values to determine, from the magnitude of said version information, which is newer programs or data,

wherein identification information is appended to a memory, provided outside of said microcomputer, in which a program or data to be used to modify a program incorporated in said microcomputer is stored, whereby said identification information is used to judge whether the memory conforms to said microcomputer control system, in which the program or data to be modified is stored,

wherein storage areas to store said identification information have a fixed address, and wherein several programs or pieces of data incorporated in said microcomputer includes programs or data not having substance.

2. A microcomputer control system according to claim 1, wherein an external device is appended to the outside of said microcomputer and a program or data to be used to modify a program incorporated in said microcomputer is supplied from said external device.

3. A microcomputer control system according to claim 2, wherein a program or data to be used to modify a program incorporated in said microcomputer is encrypted before being stored in the memory connected outside of said microcomputer.

4. A microcomputer control system according to claim 2, wherein an information recording medium reproducing device is used as said external device and the program or data to be used to modify a program incorporated in said microcomputer is recorded in an information recording medium mounted on said information recording medium reproducing device.

5. A microcomputer control system according to claim 4, wherein an optical disk is adopted as said information recording medium.