hb28b128mm2 Renesas Electronics Corporation., hb28b128mm2 Datasheet - Page 17

• Manufacturer Part Number: hb28b128mm2
• Description: Multimediacard 16 Mbyte/32 Mbyte/64 Mbyte/128 Mbyte
• Manufacturer: Renesas Electronics Corporation.

• READ_BLK_LEN
The data block length is computed as 2
Data Block Length
READ_BLK_LEN
0
1
......
11
12–15
The block length might therefore be in the range 1, 2, 4...2048 bytes. This parameter defines the block
length if READ_BLK_PARTIAL is not set. If READ_BLK_PARTIAL is set this parameter contains the
maximum allowed value of the block length in bytes. All block lengths between one and this value are
permitted. The actual block size is programmed by the command SET_BLOCKLEN (CMD16). These
Hitachi MultiMediaCards support block lengths from 1 byte up to 2048 bytes. The default value of the
parameter READ_BLK_LEN is 0x9 (512 bytes).
• READ_BLK_PARTIAL
READ_BLK_PARTIAL defines whether partial block sizes can be used in block read command.
READ_BLK_PARTIAL = 0 means that only the block size defined by READ_BLK_LEN can be used for
block-oriented data transfers. READ_BLK_PARTIAL = 1 means that smaller blocks can be used as well.
The minimum block size will be equal to minimum addressable unit (one byte). These Hitachi
MultiMediaCards support partial block read. The parameter READ_BLK_PARTIAL is permanently
assigned to the value ‘1’.
• WRITE_BLK_MISALIGN
Defines if the data block to be written by one command can be spread over more than one physical blocks
of the memory device. The size of the memory block is defined in WRITE_BLK_LEN.
WRITE_BLK_MISALIGN is permanently assigned to the value ‘0’, signaling that crossing physical block
boundaries is not 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 data block is defined in READ_BLK_LEN.
READ_BLK_MISALIGN = 0 signals that crossing physical block boundaries is not allowed.
READ_BLK_MISALIGN = 1 signals that crossing physical block boundaries is allowed. These Hitachi
MultiMediaCards do not support read block operations with boundary crossing. The parameter
READ_BLK_MISALIGN is permanently assigned to the value ‘0’.
Block length
2
2
......
2
reserved
0
1
11
= 1 byte
= 2 bytes
= 2048 bytes
READ_BLK_LEN
.
Remark
HB28H016/D032/B064/B128MM2
Rev.5.0, Jan. 2003, page 15 of 88