HB288064MM1 Datasheet, PDF (36/79 Pages) Hitachi Semiconductor – MultiMediaCard 64 MByte

HB288064MM1
• PWD: The password (new or currently used depending on the command).
The data block size shall be defined by the host before it sends the card lock/unlock command. This will
allow different password sizes. The following paragraphs define the various lock/unlock command
sequences:
• Setting the Password
—Select a card (CMD7), if not previously selected already
—Define the block length (CMD16), given by the 8bit card lock/unlock mode, the 8-bit password
size (in bytes), and the number of bytes of the new password. In case that a password replacement
is done, then the block size shall consider that both passwords, the old and the new one, are sent
with the command.
—Send Card Lock/Unlock command with the appropriate data block size on the data line
including 16 bit CRC. The data block shall indicate the mode (SET_PWD), the length
(PWD_LEN) and the password itself. In case that a password replacement is done, then the length
value (PWD_LEN) shall include both passwords, the old and the new one, and the PWD field
shall include the old password (currently used) followed by the new password.
—In case that the sent old password is not correct (not equal in size and content) then
LOCK_UNLOCK_FAILED error bit will be set in the status register and the old password
password and its size will be saved in the PWD and PWD_LEN fields, respectively.
Note that the password length register (PWD_LEN) indicates if a password is currently set. When it equals
‘0’ there is no password set. If the value of PWD_LEN is not equal to zero the card will lock itself after
power up. It is possible to lock the card immediately in the current power session by set-ting the
LOCK/UNLOCK bit (while setting the password) or sending additional command for card lock.
• Reset the Password:
—Select a card (CMD7), if not previously selected already
—Define the block length (CMD16), given by the 8 bit card lock/unlock mode, the 8 bit password
size (in bytes), and the number of bytes of the currently used password.
—Send the card lock/unlock command with the appropriate data block size on the data line
including 16 bit CRC. The data block shall indicate the mode CLR_PWD, the length
(PWD_LEN) and the password (PWD) itself (LOCK/UNLOCK bit is don’t care). If the PWD
and PWD_LEN content match the sent password and its size, then the content of the PWD
register is cleared and PWD_LEN is set to 0. If the password is not correct then the
LOCK_UNLOCK_FAILED error bit will be set in the status register.
• Locking a card:
—Select a card (CMD7), if not previously selected already
—Define the block length (CMD16), given by the 8 bit card lock/unlock mode, the 8 bit
password size (in bytes), and the number of bytes of the currently used password.
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