Chapter 3 – SD Card Interface Description
Revision 2.2
SD Card Product Manual
© 2004 SanDisk Corporation
3-22
12/08/04
3.5.5 SD
Status
Register
The SD Status Register contains status bits that are related to the SD Card proprietary
features and may be used for future application specific usage. The size of the SD Status is
one data block of 512 bits. The content of this register is transmitted to the Host over the
DAT bus along with 16 bits CRC. The SD Status is sent to the host over the DAT bus if
ACMD13 is sent (CMD55 followed with CMD13). ACMD13 can be sent to a card only in
‘tran_state’ (card selected). The SD Status structure is listed in Table 3-30. The same
abbreviations for ‘type’ and ‘clear condition’ were used as for the Card Status above.
Table 3-30
SD Card Status
Bits Identifier Type
Value
Description Clear
Cond.
511-
510
DAT_BUS_WIDTH
S R
00=1 (default)
01=reserved
10= 4-bit width
11=reserved
Shows the currently defined data
bus width that was defined by the
SET_BUS_WIDTH command
A
509
SECURED_MODE
S R
0=not in the
mode
1=secured
mode
Card is in Secured Mode of
operation (refer to the SD
Security Specifications
document).
A
508-
496
Reserved
495-
480
SD_CARD_TYPE S
R
‘00xxh’=SD
Memory Cards
as defined in
Physical Spec.
Ver.
1.01(‘x’=don’t
care).The
following cards
are currently
defined:‘0000’
=Regular SD
RD/WR
Card.‘0001’=
SD ROM Card
In the future, the 8 LSBs will be
used to define different variations
of an SD Card (each bit will
define different SD types). The 8
MSBs will be used to define SD
Cards that do not comply with
the SD Memory Card as defined
in the Specification Ver. 1.01
A
479-
448
SIZE_OF_PROTECTED_
AREA
S R
Size of
protected area
(in units of
MULT*BLOCK
_LEN refer to
CSD register).
Shows the size of the protected
area. The actual area =
(SIZE_OF_PROTECTED_AREA)
* MULT * BLOCK_LEN.
A
447-
312
Reserved
311-
0
Reserved for manufacturer
3.5.6 Relative
Card
Address
Register
The 16-bit
Relative Card Address (RCA)
Register carries the card address that is
published by the card during the card identification. This address is used for the addressed
host-card communication after the card identification procedure.