Revision 1.0 MultiMediaCardRS-MultiMediaCard Product Manual
© 2004 SanDisk Corporation 1-7
051304
1.12.6 Read and Write Operations
The MultiMediaCardRS-MultiMediaCard support two readwrite modes as shown in Figure 1-3 and defined in Table 1-2.
Figure 1-3 Data Transfer Formats
Table 1-2 Mode Definitions
Mode Description
Single Block In this mode the host reads or writes one data block in a pre-specified length. The
data block transmission is protected with 16-bit CRC that is generated by the sending unit and checked by the receiving unit.
The block length for read operations is limited by the device sector size 512 bytes but can be as small as a single byte. Misalignment is not allowed. Every data block
must be contained in a single physical sector. The block length for write operations must be identical to the sector size and the
start address aligned to a sector boundary. Multiple Block
This mode is similar to the single block mode, except for the host can readwrite multiple data blocks all have the same length that are stored or retrieved from
contiguous memory addresses starting at the address specified in the command. The operation is terminated with a stop transmission command.
Misalignment and block length restrictions apply to multiple blocks and are identical to the single block readwrite operations.
1.12.7 Data Protection in the Flash Card
Every sector is protected with an error correction code. The ECC is generated in the memory card when the sectors are written and validated when the data is read. If defects
are found, the data is corrected prior to transmission to the host.
Multiple Block Mode
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Memory Sectors
Start Address Write
Start Address ReadWrite
Start Address Read
Write Start Address
Stop Start
Read Stop
Single Block Mode Misalignment Error
Revision 1.0 MultiMediaCardRS-MultiMediaCard Product Manual
© 2004 SanDisk Corporation 1-8
051304
1.12.8 Erase The smallest erasable unit in the MultiMediaCardRS-MultiMediaCard is a sector. In order
to speed up the erase procedure, multiple sectors can be erased at the same time. The erase operation is divided into two stages as shown in Table 1-3.
Table 1-3 Erase Operation Stages
Stage Name Description
1 Tagging
Selecting the Sectors for Erasing
. To facilitate selection, a first command with the starting address is followed by a second command
with the final address, and all sectors within this range will be selected for erase.
2 Erasing
Starting the Erase Process
. The sectors are grouped into erase groups of 16 or 32 sectors. Tagging can address sectors or erase
groups. Either an arbitrary set of sectors within a single erase group, or an arbitrary selection of erase groups may be erased at one time, but
not both together. That is, the unit of measure for determining an erase is either a sector or an erase group. If sectors are tagged, then all
selected sectors must lie within the same erase group. Tagging and erasing sectors must follow a strict command sequence.
1.12.9 Write Protection
Two-card level write-protection options are available: permanent and temporary. Both can be set using the PROGRAM_CSD command refer to CSD Programming, Section 4.2.3.
The permanent write protect bit, once set, cannot be cleared. This feature is implemented in the MultiMediaCard RS-MultiMediaCard controller firmware and not with a physical OTP
cell.
1.12.10 Copy Bit
