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SPI Protocol Definition
5-10
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Table 5-2. Description of SPI Bus Commands
CMD
INDEX
SPI
Mode
Argument Resp
Abbreviation
Command
Description
CMD0
Yes
None
R1
GO_IDLE_STATE
Resets the SD Card
CMD1
Yes
None
R1
SEND_OP_COND
Activates the card’s initialization process.
CMD2 No
CMD3 No
CMD4 No
CMD5 Reserved
CMD6 Reserved
CMD7 No
CMD8 Reserved
CMD9
Yes
None
R1
SEND_CSD
Asks the selected card to send its card-specific
data (CSD).
CMD10 Yes
None
R1
SEND_CID
Asks
the
selected card to send its card
identification (CID).
CMD11 No
CMD12 Yes
None
R1b
STOP
_TRANSMISSION
Forces the card to stop transmission during a
multiple block read operation.
CMD13
Yes
None
R2
SEND_STATUS
Asks the selected card to send its status register.
CMD14 No
CMD15 No
CMD16
Yes
[31:0] block length
R1
SET_BLOCKLEN
Selects a block length (in bytes) for all following
block commands (read & write).
1
CMD17
Yes
[31:0] data address
R1
READ_SINGLE
_BLOCK
Reads a block of the size selected by the
SET_BLOCKLEN command.
2
CMD18
Yes
[31:0] data address
R1
READ_MULTIPLE
_BLOCK
Continuously transfers data blocks from card to
host until interrupted by a STOP_
TRANSMISSION command.
CMD19
Reserved
CMD20 No
CMD21
...
CMD23
Reserved
CMD24
Yes
[31:0] data address
R1
3
WRITE_BLOCK
Writes a block of the size selected by the
SET_BLOCKLEN command.
4
CMD25
Yes
[31:0] data address
R1
WRITE_MULTIPLE_BLOCK
Continuously writes blocks of data until a stop
transmission token is sent (instead of ‘start block’).
1) The only valid block length for write is 512 bytes. The valid block length for read is 1 to 512 bytes. A set block
length of less than 512 bytes will cause a write error. The card has a default block length of 512 bytes. CMD16 is
not mandatory if the default is accepted.
2) The start address and block length must be set so that the data transferred will not cross a physical block
boundary.
3) Data followed by data response plus busy.
4) The start address must be aligned on a sector boundary. The block length is always 512 bytes.