MC2GH256NMCA-2SA00 SAMSUNG [Samsung semiconductor], MC2GH256NMCA-2SA00 Datasheet - Page 50

• Manufacturer Part Number: MC2GH256NMCA-2SA00
• Description: SAMSUNG MultiMediaCard
• Manufacturer: SAMSUNG [Samsung semiconductor]

6.2.9 Erase
MultiMediaCards, in addition to the implicit erase executed by the card as part of the write operation, provides a host
explicit erase function. The erasable unit of the MultiMediaCard is the “Erase Group”; Erase group is measured in write
blocks which are the basic writable units of the card. The size of the Erase Group is a card specific parameter and defined
in the CSD. The content of an explicitly erased memory range shall be 0.
The host can erase a contiguous range of Erase Groups. Starting the erase process is a three steps sequence. First the
host defines the start address of the range using the ERASE_GROUP_START (CMD35) command, next it defines the last
address of the range using the ERASE_GROUP_END (CMD36) command and finally it starts the erase process by issu-
ing the ERASE (CMD38) command. The address field in the erase commands is an Erase Group address in byte units.
The card will ignore all LSB’s below the Erase Group size, effectively rounding the address down to the Erase Group
boundary.
If an erase command (either CMD35, CMD36, CMD38) is received out of the defined erase sequence, the card shall set
the ERASE_SEQ_ERROR bit in the status register and reset the whole sequence.
If the host provides an out of range address as an argument to CMD35 or CMD36, the card will reject the command,
respond with the ADDRESS_OUT_OF_RANGE bit set and reset the whole erase sequence.
If an ‘non erase’ command (neither of CMD35, CMD36, CMD38 or CMD13) is received, the card shall respond with the
ERASE_RESET bit set, reset the erase sequence and execute the last command. Commands not addressed to the
selected card do not abort the erase sequence.
If the erase range includes write protected blocks, they shall be left intact and only the non protected blocks shall be
erased. The WP_ERASE_SKIP status bit in the status register shall be set.
As described above for block write, the card will indicate that an erase is in progress by holding DAT0 low. The actual
erase time may be quite long, and the host may issue CMD7 to deselect the card.
6.2.10 Write Protect Management
In order to allow the host to protect data against erase or write, the MultiMediaCard shall support two levels of write protect
commands:
• The entire card may be write protected by setting the permanent or temporary write protect bits in the CSD.
• Specific segments of the cards may be write protected. The segment size is defined in units of WP_GRP_SIZE erase
The SEND_WRITE_PROT command is similar to a single block read command. The card shall send a data block contain-
ing 32 write protection bits (representing 32 write protect groups starting at the specified address) followed by 16 CRC bits.
The address field in the write protect commands is a group address in byte units. The card will ignore all LSB’s below the
group size.
If the host provides an out of range address as an argument to CMD28, CMD29 or CMD30, the card will reject the com-
mand, respond with the ADDRESS_OUT_OF_RANGE bit set and remain in the Tran state.
Revision 0.3
groups as specified in the CSD. The SET_WRITE_PROT command sets the write protection of the addressed write-pro
tect group, and the CLR_WRITE_PROT command clears the write protection of the addressed write-protect group.
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MultiMediaCard
Sep.22.2005
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