Chapter 4 – SD Card Protocol Description
Revision 2.2 SanDisk SD Card Product Manual
© 2004 SanDisk Corporation 4-35 12/08/04
CMD Index Type Argument Resp. Abbreviation Description
(representing 32 write-
protect groups starting at
the specified address)
followed by 16 CRC bits
are transferred in a
payload format via the
data line. The last (least
significant) bit of the
protection bits
corresponds to the first
addressed group. If the
addresses of the last
groups are outside the
valid range, then the
corresponding write-
protection bits shall be
set to zero.
CMD31 Reserved
Erase Commands (Class 5)
CMD32 ac [31:0] data
address
R1 ERASE_WR_BLK_START Sets the address of the
first write block to be
erased.
CMD33 ac [31:0] data
address
R1 ERASE_WR_BLK_END Sets the address of the
last write block of the
continuous range to be
erased.
CMD38 ac [31:0] don’t
care
R1b ERASE Erases all previously
selected write blocks.
CMD39 Reserved
CMD40 --- --- --- --- Not valid in SD Memory
Card -Reserved for
MultiMediaCard I/O
mode.
CMD41 Reserved
I/O Mode Commands (Class 9)
CMD39
CMD40
MMCA Optional Command, currently not supported.
CMD41 Reserved
Lock Card Commands (Class 7)
CMD16 ac [31:] block
length
R1 SET_BLOCKLEN Sets the block length (in
bytes) for all following
block commands (read,
write, lock). Default
block length is specified
in the CSD. Supported
only if Partial block
RD/WR operation are
allowed in CSD.
CMD42 adtc [31:0] stuff
bits
R1 LOCK_UNLOCK Used to set/reset the
password or lock/unlock
the card. The size of the
data block is set by the
SET_BLOCK_LEN
command.
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