Data processing system including corrupt flash ROM recovery

  • US 5,327,531 A
  • Filed: 09/21/1992
  • Issued: 07/05/1994
  • Est. Priority Date: 09/21/1992
  • Status: Expired due to Fees
First Claim
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1. In a personal computer comprising a non-volatile primary flash read only memory (ROM) for storing initialization information including a first reset vector containing a jump instruction, said flash ROM having a predetermined first location for storing said first reset vector, a non-volatile secondary ROM for storing initialization information including a second reset vector containing a jump instruction for ranching to initialization code, said secondary ROM having a second predetermined location for storing said second reset vector, a microprocessor for reading said first location in response to a CPU reset signal, a memory controller for controlling operation of said flash ROM and said secondary ROM, and bus means interconnecting said microprocessor, said ROMs, and said memory controller, the improvement comprising:

  • first means in said memory controller connected to said bus means for detecting a corrupted flash ROM, when said microprocessor is reading said first location, and generating a CPU reset signal in response thereto;

    second means connected to said first means for receiving said CPU reset signal therefrom and switching said second ROM to become a primary ROM; and

    third means connected from said first means to said microprocessor for transmitting said CPU reset signal thereto, whereby said microprocessor is reset causing said jump instruction in said second reset vector to be fetched from said second ROM and executed to thereby branch to said initialization code and initialize said personal computer using initialization information in said second ROM.

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