Intel compatible flash device issue

MarekSk mareksk7 at
Tue Jun 22 15:03:29 EDT 2004

  I have encountered a problem using M28W160CT flash chip as
  LINUX character device. This chips is compatible with INTEL standard
  command set.

  Since the chip is locked after power-up, there is required to unlock
  some blocks before write operation. Of course, this can be done
  from any application using MEMUNLOCK command.

  Once the MEMUNLOCK command is executed (without any error)
  the flash chip remains in the "command" state.
  This state after MEMUNLOCK blocks any read access to data stored
  in the flash.

  Reviewing the cfi_cmdset_0001.c file I have found that single block
  (un)lock algorithm (do_xxlock_oneblock) is different from these
  described in the following documents:
  - STM M28W160CT datasheet (figure 22)
  - Intel 28F160C3 datasheet (figure 20)

  It seems that there should be issued the reset command (0xff) just
  after lock (0x01)/unlock (0xd0) command.

  Any comments, ideas ?

Thanks in advance,

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