HB288064MM1 Datasheet, PDF (21/79 Pages) Hitachi Semiconductor – MultiMediaCard 64 MByte

HB288064MM1
MultiMediaCard Communication
All communication between host and cards is controlled by the host (master). The host sends commands
and, depending on the command, receives a corresponding response from the selected card. In this chapter
the commands to control the HB288064MM1, the card responses and the contents of the status and error
field included in the responses, are defined.
Memory Array Partitioning
The basic unit of data transfer to/from the MultiMediaCard is one byte. All data transfer operations which
require a block size always define block lengths as integer multiples of bytes. Some special functions need
other partition granularity. For block-oriented commands, the following definition is used:
• Block: is the unit which is related to the block-oriented read and write commands. Its size is the
number of bytes which will be transferred when one block command is sent by the host. The size of a
block is either programmable or fixed. The information about allowed block sizes and the
programmability is stored in the CSD.
For devices which have erasable memory cells, special erase commands are defined. The granularity of the
erasable units is in general not the same as for the block-oriented commands:
• Sector: is the unit which is related to the erase commands. Its size is the number of blocks which will
be erased in one portion. The size of a sector is fixed for each device. The information about the sector
size (in blocks) is stored in the CSD.
• Group: is a number of sectors. Its size is the number of consecutive sectors which will be erased at
once. The size of a group is fixed for each device. The information about the size is stored in the CSD.
For devices which include a write protection:
• WP-Group: is the minimal unit which may have individual write protection. Its size is the number of
sectors which will be write protected by one bit. The size of a WP-group is fixed for each device. The
information about the size is stored in the CSD.
Each erasable unit (group and sector) has a special “tag” bit. This bit may be set or cleared by special
commands to tag the unit. All tagged units will be erased in parallel by one erase command following a
number of tag commands. All tag bits are cleared by each command except a tag or untag command.
Therefore, immediately after a sequence of tag commands an erase command has to be sent by the host.
Commands others than tagging or erasing abort a tag-erase cycle irregularly.
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