Product manual

Industrial Grade SD Card Interface Description

Table 3-21. Data Block Length

WRITE_BL_LEN Block Length

0-8 Reserved

9 29 = 512 Bytes

….

11 211 = 2048 Bytes

12-15 Reserved

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 blocks, 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.

FILE_FORMAT_GROUP—Indicates the selected group of file formats. This field is read-only for ROM. The

usage of this field is shown in Table 3-22.

COPY—This bit marks the card as an original (‘0’) or non-original (‘1’). Once set to non-original, this bit cannot

be reset to original. The definition of “original” and “non-original” is application dependent and changes no card

characteristics.

PERM_WRITE_PROTECT—Permanently protects the whole card content, except the secured protected area,

against overwriting or erasing (all write and erase commands for this card are permanently disabled). The default

value is ‘0’, i.e., not permanently write protected.

TMP_WRITE_PROTECT—Temporarily protects the whole card content, except the secured protected area, from

being overwritten or erased (all write and erase commands for this card are temporarily disabled). This bit can be set

and reset. The default value is ‘0’, i.e., not write protected.

FILE_FORMAT—Indicates the file format on the card. This field is read-only for ROM. The following formats

are defined.

Table 3-22. File Format

FILE_FORMAT_GRP FILE_FORMAT Type

0 0 Hard disk-like file system with partition table

0 1 DOS FAT (floppy-like) with boot sector only (no partition table)

0 2 Universal File Format

0 3 Others/Unknown

1 0, 1, 2, 3 Reserved

CRC—The CRC field carries the check sum for the CSD contents. The checksum has to be recalculated by the host

for any CSD modification. The default corresponds to the initial CSD contents.