MultiMediaCard Product Manual
32
SanDisk MultiMediaCard Product Manual Rev. 2 © 2000 SANDISK CORPORATION
CCC
—The MultiMediaCard 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. For command class definition refer to
Table 5-2.
Table 4-11 Supported Card Command Classes
CCC bit
Supported Card Command Class
0
class 0
1
class 1
......
11
class 11
READ_BL_LEN
—The data block length is computed as 2
READ_BL_LEN
. The block length might therefore
be in the range 1, 2,4...2048 bytes:
Table 4-12 Data Block Length
READ_BL_LEN
Block Length
Remark
0
2
0
= 1 Byte
1
2
1
= 2 Bytes
......
11
2
11
= 2048 Bytes
12-15
reserved
READ_BL_PARTIAL
—Defines whether partial block sizes can be used in block read commands.
READ_BL_PARTIAL=0 means that only the READ_BL_LEN block size can be used for block oriented
data transfers.
READ_BL_PARTIAL=1 means that smaller blocks can be used as well. The minimum block size will be
equal to minimum addressable unit (one byte)
WRITE_BLK_MISALIGN
—Defines if the data block to be written by one command can be spread over
more than one physical block of the memory device. The size of the memory block is defined in
WRITE_BL_LEN.
WRITE_BLK_MISALIGN=0 signals that crossing physical block boundaries is invalid.
WRITE_BLK_MISALIGN=1 signals that crossing physical block boundaries is allowed.
READ_BLK_MISALIGN
—Defines if the data block to be read by one command can be spread over more
than one physical block of the memory device. The size of the memory block is defined in
READ_BL_LEN.
READ_BLK_MISALIGN=0 signals that crossing physical block boundaries is invalid.
READ_BLK_MISALIGN=1 signals that crossing physical block boundaries is allowed.
DSR_IMP
—Defines if the configurable driver stage is integrated on the card. If set, a driver stage
register (DSR) must be implemented also.