Datasheet

S
S
S
D
D
D
H
H
H
C
C
C
1
1
1
0
0
0
C
C
C
a
a
a
r
r
r
d
d
d
s
s
s
e
e
e
r
r
r
i
i
i
e
e
e
s
s
s
Rev. 1.0
4~32GB High Capacity Secure Digital Card
Transcend Information Inc.
17
Note that for current SD Memory Cards that field must be always 0_0110_010b (032h) which is equal to 25MHz - the
mandatory maximum operating frequency of SD Memory Card.
In High-Speed mode, that field must be always 0_1011_010b (05Ah) which is equal to 50MHz. And when the timing
mode returns to the default by CMD6 or CMD0 command, its value will be 032h.
•
CCC
The SD Memory Card command set is divided into subsets (command classes). The card command class register
CCC defines which command classes are supported by this card. A value of ‘1’ in a CCC bit means that the
corresponding command class is supported.
CCC bit Supported card command class
0 class 0
1 class 1
......
11 class 11
Supported Card Command Classes
•
READ_BL_LEN
This field is fixed to 9h, which indicates READ_BL_LEN=512 Byte.
• READ_BL_PARTIAL
This field is fixed to 0, which indicates partial block read is inhibited and only unit of block access is allowed.
•
WRITE_BLK_MISALIGN
This field is fixed to 0, which indicates that write access crossing physical block boundaries is always disabled in SDHC
and SDXC Cards.
•
READ_BLK_MISALIGN
This field is fixed to 0, which indicates that read access crossing physical block boundaries is always
disabled in SDHC and SDXC Cards.
•
DSR_IMP
Defines if the configurable driver stage is integrated on the card. If set, a driver stage register (DSR) must be
implemented also.