SanDisk SDSDB-32-201-80 - Industrial Grade Flash Memory Card Product Manual page 41

SD Card Interface Description
READ_BL_LEN—The maximum read data block length is computed as 2
might therefore be in the range 512...2048 bytes. Note that in the SD Card, the WRITE_BL_LEN is always equal to
READ_BL_LEN.
READ_BL_PARTIAL— READ_BL_PARTIAL is always set to 1 in the SD Card. Partial Block Read is always
allowed in the SD Card. It means that smaller blocks can be used as well. The minimum block size is one byte.
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.
3-16
Table 3-14. Supported Card Command Classes
CCC Bit Supported Card Command Class
0
1
......
11
Table 3-15. Data Block Length
READ_BL_LEN
0-8
9
......
11
12-15
Table 3-16. DSR Implementation Code Table
DSR_IMP
0 no DSR implemented
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
class 0
class 1
class 11
READ_BL_LEN
. The maximum block length
Block Length
Reserved
2 = 512 Bytes
9
2 = 2048 Bytes
11
Reserved
DSR Type