SD Card Interface Description
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-23
3.5.6. SD Status
The SD Status 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 3-29. The same abbreviations for ‘type’ and ‘clear condition’
were used as for the Card Status above.
Table 3-29. 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’=in 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_A
REA) * MULT *
BLOCK_LEN.
A
447:
312
Reserved
311:
0
Reserved for Manufacturer
3.5.7. RCA Register
The 16-bit relative card address 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.
