Memory Card Specification Sheet

©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
15
4. Differences with SD Memory Specification
4.1 SDIO Command List
Table A-14 shows the list of commands accepted by SD memory and SDIO cards when using the SD bus
interface. Table A-15 shows the list of commands accepted by SD memory and SDIO cards when using the SPI
bus interface.
4.2 Unsupported SD Memory Commands
Several commands required for SD Memory cards are not supported by either SDIO-only cards or the I/O
portion of Combo cards. Some of these commands have no use in SDIO cards such as Erase commands and
thus are not supported in SDIO. In addition, there are several commands for SD memory cards that have
different commands when used with the SDIO section of a card. Table 4-1 lists these SD Memory commands
and the equivalent SDIO commands. For a complete list of supported and unsupported commands, see Table
A-14 and Table A-15.
SD Memory
Command
SDIO
Command
Comment
CMD0 CMD52 (write to
I/O reset in
CCCR)
The reset command (CMD0) is only used for memory or the
memory portion of Combo cards. In order to reset an I/O only
card or the I/O portion of a combo card, use CMD52 to write a
1 to the RES bit in the CCCR (bit 3 of register 6). Note that in
the SD mode, CMD0 is only used to indicate entry into SPI
mode and shall be supported. An I/O only card or the I/O
portion of a combo card is not reset with CMD0
CMD12 CMD52 (write to
I/O abort)
In order to abort the block transfer of data, SD memory use
CMD12. In order to abort an I/O transaction, use CMD52 to
write to the abort register in the CCCR (bits 2:0 of register 6)
See 4.8 for details.
CMD16 CMD52 (write to
I/O Block
Length)
CMD16 sets the block length for SD memory. In order to set
the block length for each I/O function, use CMD52 to write the
block length in the FBR
CMD2 NONE The CID register does not exist in an SDIO only card
CMD4 NONE The DSR register does not exist in an SDIO only card
CMD9 NONE The CSD register does not exist in an SDIO only card
CMD10 NONE The CID register does not exist in an SDIO only card
CMD13 NONE An SDIO only card or the I/O portion of a combo card does not
support the same SEND_STATUS (CMD13) protocol the SD
memory uses. See 4.10.8.
ACMD6 CMD52 (write to
Bus_Width [1:0]
in CCCR)
SET_BUS_WIDTH is handled by a write to the CCCR. See
4.4 for details.
ACMD13 NONE The SD Status register does not exist in an SDIO only card
ACMD41 CMD5 SDIO cards and hosts use the IO_SEND_OP_COND
Command (CMD5). See 3.2
ACMD42 CMD52 In the SD mode, the pull-up resistor on DAT[3] is controlled by
writing to the
CD Disable bit in the CCCR. For Combo Cards,
this resistor is enabled unless both the memory and the I/O
control registers are set to disable the resistor. For details, see
section 4.6
ACMD51 NONE The SCR register does not exist in an SDIO only card
CMD17, CMD53 I/O block operations use CMD53, rather than memory block