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Fault tolerant smart card

  • US 4,908,502 A
  • Filed: 02/08/1988
  • Issued: 03/13/1990
  • Est. Priority Date: 02/08/1988
  • Status: Expired due to Term
First Claim
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1. A fault tolerant smart card comprising:

  • a standard input-output interface;

    clock means for providing a time reference during smart card operations;

    main memory means for storing program and data information;

    first microcontroller means connected to said interface, said clock means and said main memory means for performing normal smart card functions;

    secondary microcontroller means connected to said first microcontroller means, said clock means, said main memory means and to secondary memory means for performing normal smart card functions in synchronization with said first microcontroller means;

    microcontroller error detection means connected to said first microcontroller means and said secondary microcontroller means for detecting a failure of either of said first or secondary microcontrollers; and

    primary power supply means connected to said first microcontroller means.

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