NONVOLATILE MEMORY DATA PROTECTION USING NONVOLATILE PROTECTION CODES AND VOLATILE PROTECTION CODES

摘要

Methods for protecting data on an integrated circuit including a memory are described. One method includes storing nonvolatile protection codes on the integrated circuit. The nonvolatile protection codes have a first value indicating a protected state or a second value indicating an unprotected state for respective sectors in a plurality of sectors of the memory. The method includes storing volatile protection codes on the integrated circuit. The volatile protection codes have a first value indicating a protected state or a second value indicating an unprotected state for respective sectors in the plurality of sectors. The method includes blocking modification in a particular sector using circuitry on the integrated circuit when the volatile protection code for the particular sector has the first value, else allowing modification in the particular sector, and setting the volatile protection codes to values of the nonvolatile protection codes in an initialization procedure.

主权项

1. A circuit comprising:
a nonvolatile memory array comprising a plurality of sectors of nonvolatile memory cells; an array of nonvolatile memory elements, each nonvolatile memory element in the array storing a nonvolatile protection code having a first value indicating a protected state or a second value indicating an unprotected state for a corresponding sector in the plurality of sectors; an array of volatile memory elements, each volatile memory element in the array storing a volatile protection code having a first value indicating a protected state or a second value indicating an unprotected state for a corresponding sector in the plurality of sectors; and control logic coupled to the memory array, which blocks modification in a particular sector when the volatile protection code for the particular sector has the first value, else allows modification in the particular sector, and which sets the volatile protection codes to the values of nonvolatile protection codes in an initialization procedure.