Chapter 4 – SD Card Protocol Description
Revision 2.2
SanDisk SD Card Product Manual
© 2004 SanDisk Corporation
4-36
12/08/04
CMD Index
Type
Argument
Resp.
Abbreviation
Description
CMD43 …
CMD51
Reserved
Application-specific Commands (Class 8)
CMD55 ac
[31:16]
RCA [15:0]
stuff bits
R1
APP_CMD
Indicates to the card that
the next command is an
application-specific
command rather than a
standard command
CMD56 adtc
[31:1]
stuff
bits [0]
RD/WR
R1
GEN_CMD
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.
RD/WR: “1” the host
gets a block of data from
the card. “0” the
host sends block of data
to the card.
All the application-
specific commands are
supported if Class 8 is
allowed (mandatory in
SD Card).
CMD58-CMD59 Reserved
CMD60-CMD63
Reserved for manufacturer
I/O Mode Commands (Class 9)
CMD52…CMD54 Reserved for I/O mode (refer to SDIO Card Specification.
Switch Function Commands (Class 10)
CMD6
adtc
[31] Mode 0
0:Check function
1:Switch function
[30:24] Reserved (all 0)
[23:20] Reserved for function
group 6 (all 0 or 0xF)
[19:16] Reserved for function
group 5 (all 0 or 0xF)
[15:12] Reserved for function
group 4 (all 0 or 0xF)
[11:8] Reserved for function
group 3 (all 0 or 0xF)
[7:4] Function group 2 for
command system
[3:0] Function group 1 for
access mode.
R1 SWITCH_FUNC
Checks
switchable
function (mode 0)
and switch card
function (mode 1).
CMD34
CMD35
CMD36
CMD37
CMD50
Reserved for each command system set by switch function command (CMD6). For detailed
definitions, refer to each command system specification.