Program rewriting method and apparatus for multiprocessor system
First Claim
1. A method of rewriting, by a first microprocessor in a first microprocessor system, contents of a program memory for a second microprocessor in a second microprocessor system and vice versa, said first microprocessor system including said first microprocessor, a first rewritable program memory for storing therein an executable program for said first microprocessor, and a first system bus connected to said first microprocessor and said first rewritable program memory, and said second microprocessor system including said second microprocessor, a second rewritable program memory for storing therein an executable program for said second microprocessor, and a second system bus connected to said second microprocessor and said second rewritable program memory, said second system bus being separate from said first system bus, said method comprising the steps of:
- releasing said second system bus by said second microprocessor, in response to a request from said first microprocessor;
supplying from said first system bus an address on said second system bus thus released under control of said first microprocessor;
reading data of a new program from a common memory connected to said first and second system buses and commonly accessible by said first and second microprocessors under control of said first and second microprocessors;
supplying from said first system bus the data thus read on said second system bus thus released under control of said first microprocessor; and
rewriting the data thus supplied on said second system bus in said second program memory by performing data write operation of said second program memory under control of said first microprocessor.
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Accused Products
Abstract
In at least two microprocessor systems each having a microprocessor, a flash electrically erasable programmable read only memory (EEPROM), and a system bus connected to the microprocessor and the memory, there is disposed a controller between the system buses of the respective systems. The processor of one of the systems rewrites a program in the memory of a remaining system via the system bus of the remaining system.
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Citations
16 Claims
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1. A method of rewriting, by a first microprocessor in a first microprocessor system, contents of a program memory for a second microprocessor in a second microprocessor system and vice versa, said first microprocessor system including said first microprocessor, a first rewritable program memory for storing therein an executable program for said first microprocessor, and a first system bus connected to said first microprocessor and said first rewritable program memory, and said second microprocessor system including said second microprocessor, a second rewritable program memory for storing therein an executable program for said second microprocessor, and a second system bus connected to said second microprocessor and said second rewritable program memory, said second system bus being separate from said first system bus, said method comprising the steps of:
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releasing said second system bus by said second microprocessor, in response to a request from said first microprocessor; supplying from said first system bus an address on said second system bus thus released under control of said first microprocessor; reading data of a new program from a common memory connected to said first and second system buses and commonly accessible by said first and second microprocessors under control of said first and second microprocessors; supplying from said first system bus the data thus read on said second system bus thus released under control of said first microprocessor; and rewriting the data thus supplied on said second system bus in said second program memory by performing data write operation of said second program memory under control of said first microprocessor. - View Dependent Claims (2, 3)
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4. An apparatus for rewriting, by a first microprocessor in a first microprocessor system, contents of a program memory for a second microprocessor in a second microprocessor system and vice versa, comprising:
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said first microprocessor system, including said first microprocessor, further includes a first rewritable program memory for storing therein an executable program for said first microprocessor, and a first system bus connected to said first microprocessor and said first rewritable program memory; said second microprocessor system, including said second microprocessor, further includes a second rewritable program memory for storing therein an executable program for said second microprocessor, and a second system bus connected to said second microprocessor and said second rewritable program memory, said second system bus being separate from said first system bus; storage means connected to said first and second system buses, for storing therein a new program for a rewrite operation, said storage means being commonly accessible for a read operation from said first and second microprocessors through said first and second system buses, respectively under control of said first and second microprocessors; a request line for transmitting a request from said first microprocessor to said second microprocessor to cause said second microprocessor to release said second system bus; and means connected between said first and second system buses for replacing, in accordance with execution under control of said first microprocessor, contents of said second rewritable program memory with contents of said storage means by reading data from said storage means on said first system bus and transferring the data thus read to said second system bus after said second system bus is released by the request from said first microprocessor. - View Dependent Claims (5, 6, 7)
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8. A program rewriting apparatus comprising:
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a first microprocessor system including a first microprocessor, a first rewritable memory for storing a program and a first system bus connected to said first microprocessor and said first rewritable memory, said first microprocessor reading out the program stored in said first rewritable memory through said first system bus to execute the program read out; a second microprocessor system including a second microprocessor, a second rewritable memory for storing a program and a second system bus connected to said second microprocessor and said second rewritable memory, said second system bus being separate from said first system bus, and said second microprocessor reading out the program stored in said second rewritable memory through said second system bus to execute the program read out from said second rewritable memory, independently of execution by said first microprocessor; a common memory provided to be accessible commonly to said first and second microprocessor systems under control of said first and second microprocessor systems; and a controller connected to said first and second microprocessor systems and responsive to a request from a microprocessor of one microprocessor system, for causing a microprocessor of the other microprocessor system to release a system bus of said the other microprocessor system, so that the microprocessor of said one microprocessor system rewrites contents of a rewritable memory of the other microprocessor system using an update program stored in said common memory. - View Dependent Claims (9, 10, 11, 12)
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13. A disk device comprising:
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a first microprocessor system for controlling data read/write operation of a disk drive, said first microprocessor system including a first microprocessor, a first rewritable memory for storing a program and a first system bus connected with said first microprocessor and said first rewritable memory, said first microprocessor reading out the program stored in said first rewritable memory through said first system bus to execute the program read out; a second microprocessor system for controlling driving operation of heads in said disk drive, said second microprocessor system including a second microprocessor, a second rewritable memory for storing a program and a second system bus connected with said second microprocessor rand said second rewritable memory, said second system bus being separate from said first system bus, and said second microprocessor reading out the program stored in said second rewritable memory through said second system bus to execute the program read out from said second rewritable memory, independently of execution by said first microprocessor; a common memory provided to be accessible commonly to said first and second microprocessor systems under control of said first and second microprocessor systems; and a controller connected with said first and second microprocessor systems and responsive to a request from a microprocessor of one microprocessor system, for causing a microprocessor of the other microprocessor system to release a system bus of said other microprocessor system, so that the microprocessor of said one microprocessor system rewrites contents of a rewritable memory of said other microprocessor system using an update program stored in said common memory. - View Dependent Claims (14, 15, 16)
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Specification