HB28D032MM2 datasheet(24/90 Pages) RENESAS

24 / 90 page

HB28H016/D032/B064/B128MM2

Rev.5.0, Jan. 2003, page 22 of 88

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 these Hitachi MultiMediaCards, 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:

• Sector: is the unit which is related to the tagged sector commands (CMD32 to CMD34). In these

Hitachi MultiMediaCards, this size is same as the WRITE_BLK_LEN in CSD.

• Erase Group: is the smallest number of consecutive write blocks, which can be addressed for erased.

The size of the Erase Group is card specific and 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

erase groups 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 (erase 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.

HB28D032MM2 Datasheet(PDF) 24 Page - Renesas Technology Corp