Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
120
• SECTOR_SIZE
The size of an erasable sector. The content of this register is a 7-bit binary coded value, defining the
number of write blocks (see WRITE_BL_LEN). The actual size is computed by increasing this number
by one. A value of zero means one write block, 127 means 128 write blocks.
• WP_GRP_SIZE
The size of a write protected group. The content of this register is a 7-bit binary coded value, defining
the number of erase sectors (see SECTOR_SIZE). The actual size is computed by increasing this
number by one. A value of zero means one erase sector, 127 means 128 erase sectors.
• WP_GRP_ENABLE
A value of 0 means no group write protection possible.
• R2W_FACTOR
Defines the typical block program time as a multiple of the read access time. The following table defines
the field format.
R2W_FACTOR
Multiples of read access time
0
1
1
2 (write half as fast as read)
2
4
3
8
4
16
5
32
6,7
reserved
Table 5-13: R2W_FACTOR
• WRITE_BL_LEN
The maximum write data block length is computed as 2
WRITE_BL_LEN
. The maximum block length might
therefore be in the range from 512 to 2048 bytes. Write Block Length of 512 bytes is always supported.
Note that in the SD Memory Card, the WRITE_BL_LEN is always equal to READ_BL_LEN.
WRITE_BL_LEN
Block Length
0-8
reserved
9
2
9
= 512 bytes
10
2
10
= 1024 Bytes
11
2
11
= 2048 Bytes
12-15
reserved
Table 5-14: Data Block Length
• WRITE_BL_PARTIAL
Defines whether partial block sizes can be used in block write commands.
WRITE_BL_PARTIAL=0 means that only the WRITE_BL_LEN block size and its partial derivatives, in
resolution of units of 512 bytes, can be used for block oriented data write.
WRITE_BL_PARTIAL=1 means that smaller blocks can be used as well. The minimum block size is one
byte.