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Selecting erase method based on type of power supply for flash EEPROM

  • US 5,933,847 A
  • Filed: 09/24/1996
  • Issued: 08/03/1999
  • Est. Priority Date: 09/28/1995
  • Status: Expired due to Fees
First Claim
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1. A flash ROM management apparatus comprising:

  • managing means for forming a plurality of storage blocks each consisting of a data area and a management area corresponding to the data area in a flash ROM, storing state information indicating a storage state of the data area of each storage block in the management area of the storage block, and managing access to said flash ROM on the basis of the state information;

    first erasing means for extracting, from one erase block of said flash ROM, on the basis of the state information, a storage block in which valid data exists in the data area, moving contents of the extracted storage block, and erasing the erase block;

    second erasing means for extracting, from a plurality of erase blocks, on the basis of the state information, storage blocks in which valid data exists in the data area, moving contents of the extracted storage blocks to a storage area including a random access memory, and erasing the erase blocks; and

    executing means for selecting one of said first erasing means and said second erasing means and executing an erase operation on the basis of the type of power supply of an apparatus into which said flash ROM is incorporated.

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