Secure Digital (SD) Card Protocol Description
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
4-23
Table 4-10 describes all the application specific commands supported/reserved by the SD Card. All the following
ACMDs shall be preceded with APP_CMD command (CMD55)
.
Table 4-10. Application Specific Commands Used/Reserved by SD Card
ACMD
INDEX
Type Argument Resp. Abbreviation
Command
Description
ACMD6
ac
[31:2] stuff bits
[1:0]bus width
R1
SET_BUS_WIDTH
Defines the data bus width (’00’=1bit or ’10’=4 bits bus)
to be used for data transfer.
ACMD13
adtc
[31:0] stuff bits
R1 SD_STATUS
Send the SD Card status. The status fields are given in
Table 4-28.
ACMD17 Reserved
ACMD18 --
--
--
--
Reserved
for
SD security applications.
1
ACMD19
to
ACMD21
Reserved
ACMD22
adtc
[31:0] stuff bits
R1
SEND_NUM_WR_
BLOCKS
Send the number of the written (without errors) write
blocks. Responds with 32bit+CRC data block.
ACMD23
ac
[31:23] stuff bits
[22:0]Number of blocks
R1 SET_WR_BLK_
ERASE_COUNT
Set the number of write blocks to be pre-erased before
writing (to be used for faster Multiple Block WR
command). “1”=default (one wr block)
2
.
ACMD24 Reserved
ACMD25 --
--
--
--
Reserved
for
SD security applications.
1
ACMD26 --
--
--
--
Reserved
for
SD security applications.
1
ACMD38 --
--
--
--
Reserved
for
SD security applications.
1
ACMD39
to
ACMD40
Reserved
ACMD41 bcr [31:0]OCR
without busy
R3
SD_APP_OP_COND
Asks the accessed card to send its operating condition
register (OCR) con tent in the response on the CMD
line.
ACMD42
ac
[31:1] stuff bits
[0]set_cd
R1 SET_CLR_CARD_
DETECT
Connect[1]/Disconnect[0] the 50KOhm pull-up resistor
on CD/DAT3 (pin 1) of the card. The pull-up may be
used for card detection.
ACMD43
ACMD49
--
--
--
--
Reserved for SD security applications.
1
ACMD51
adtc
[31:0] staff bits
R1
SEND_SCR
Reads the SD Configuration Register (SCR).
NOTES: 1) Refer to
SD Card Security Specification
for detailed explanation about the SD Security Features
2) Command STOP_TRAN (CMD12) shall be used to stop the transmission in Write Multiple Block whether the pre-
erase (ACMD23) feature is used or not.
