
SD/SDIO/MMC card host interface (SDMMC)
RM0351
1554/1830
DocID024597 Rev 5
45.5 Response
formats
All responses are sent via the SDMMC command line SDMMC_CMD. The response
transmission always starts with the left bit of the bit string corresponding to the response
code word. The code length depends on the response type.
A response always starts with a start bit (always 0), followed by the bit indicating the
direction of transmission (card = 0). A value denoted by x in the tables below indicates a
variable entry. All responses, except for the R3 response type, are protected by a CRC.
Every command code word is terminated by the end bit (always 1).
There are five types of responses. Their formats are defined as follows:
CMD40 bcr
[31:0] stuff bits
R5
GO_IRQ_STATE
Places the system in the interrupt mode.
CMD41 Reserved
Table 285. I/O mode commands (continued)
CMD
index
Type
Argument
Response
format
Abbreviation
Description
Table 286. Lock card
CMD
index
Type
Argument
Response
format
Abbreviation
Description
CMD42 adtc
[31:0] stuff bits R1b
LOCK_UNLOCK
Sets/resets the password or locks/unlocks
the card. The size of the data block is set
by the SET_BLOCK_LEN command.
CMD43
...
CMD54
Reserved
Table 287. Application-specific commands
CMD
index
Type
Argument
Response
format
Abbreviation
Description
CMD55
ac
[31:16] RCA
[15:0] stuff bits
R1
APP_CMD
Indicates to the card that the next command
bits is an application specific command rather
than a standard command
CMD56
adtc
[31:1] stuff bits
[0]: RD/WR
-
-
Used either to transfer a data block to the card
or to get a data block from the card for general
purpose/application-specific commands. The
size of the data block shall be set by the
SET_BLOCK_LEN command.
CMD57
...
CMD59
Reserved.
CMD60
...
CMD63
Reserved for manufacturer.