
SD/SDIO/MMC card host interface (SDMMC)
RM0351
1552/1830
DocID024597 Rev 5
Command types
Both application-specific and general commands are divided into the four following types:
•
broadcast command (BC)
: sent to all cards; no responses returned.
•
broadcast command with response (BCR):
sent to all cards; responses received
from all cards simultaneously.
•
addressed (point-to-point) command (AC):
sent to the card that is selected; does
not include a data transfer on the SDMMC_D line(s).
•
addressed (point-to-point) data transfer command (ADTC):
sent to the card that is
selected; includes a data transfer on the SDMMC_D line(s).
Command formats
See
for command formats.
Commands for the MultiMediaCard/SD module
Table 282. Block-oriented write commands
CMD
index
Type
Argument
Response
format
Abbreviation
Description
CMD23 ac
[31:16] set to 0
[15:0] number
of blocks
R1
SET_BLOCK_COUNT
Defines the number of blocks which
are going to be transferred in the
multiple-block read or write command
that follows.
CMD24 adtc
[31:0] data
address
R1
WRITE_BLOCK
Writes a block of the size selected by
the SET_BLOCKLEN command.
CMD25 adtc
[31:0] data
address
R1
WRITE_MULTIPLE_BLOCK
Continuously writes blocks of data
until a STOP_TRANSMISSION
follows or the requested number of
blocks has been received.
CMD26 adtc
[31:0] stuff bits R1
PROGRAM_CID
Programming of the card identification
register. This command must be
issued only once per card. The card
contains hardware to prevent this
operation after the first programming.
Normally this command is reserved
for manufacturer.
CMD27 adtc
[31:0] stuff bits R1
PROGRAM_CSD
Programming of the programmable
bits of the CSD.