HB28D032MM2 datasheet(17/90 Pages) RENESAS

17 / 90 page

HB28H016/D032/B064/B128MM2

Rev.5.0, Jan. 2003, page 15 of 88

• READ_BLK_LEN

The data block length is computed as 2

READ_BLK_LEN.

Data Block Length

READ_BLK_LEN

Block length

Remark

0 = 1 byte

1 = 2 bytes

......

11 = 2048 bytes

12–15

reserved

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’.

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