RM0090: Reference manual - STMicroelectronics

RM0090 Secure digital input/output interface (SDIO)
The bus transaction for a GEN_CMD is the same as the single-block read or write
commands (WRITE_BLOCK, CMD24 or READ_SINGLE_BLOCK,CMD17). In this case, the
argument denotes the direction of the data transfer rather than the address, and the data
block has vendor-specific format and meaning.
The card must be selected (in transfer state) before sending GEN_CMD (CMD56). The data
block size is defined by SET_BLOCKLEN (CMD16). The response to GEN_CMD (CMD56)
is in R1b format.
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 SDIO_D line(s).
● addressed (point-to-point) data transfer command (ADTC): sent to the card that is
selected; includes a data transfer on the SDIO_D line(s).
Command formats
See Table 127 on page 850 for command formats.
Commands for the MultiMediaCard/SD module
Table 143. Block-oriented write commands
CMD
index
CMD23 ac
CMD24 adtc
CMD25 adtc
Type Argument
[31:16] set to 0
[15:0] number
of blocks
[31:0] data
address
[31:0] data
address
Response
format
R1 SET_BLOCK_COUNT
R1 WRITE_BLOCK
R1 WRITE_MULTIPLE_BLOCK
CMD26 adtc [31:0] stuff bits R1 PROGRAM_CID
CMD27 adtc [31:0] stuff bits R1 PROGRAM_CSD
Abbreviation Description
Defines the number of blocks which
are going to be transferred in the
multiple-block read or write command
that follows.
Writes a block of the size selected by
the SET_BLOCKLEN command.
Continuously writes blocks of data
until a STOP_TRANSMISSION
follows or the requested number of
blocks has been received.
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.
Programming of the programmable
bits of the CSD.
Doc ID 018909 Rev 3 874/1416