SDMJ-32 SanDisk, SDMJ-32 Datasheet - Page 5

• Manufacturer Part Number: SDMJ-32
• Manufacturer: SanDisk
• Type: MultiMedia Cardr

Specifications of SDMJ-32

• Density: 32MByte
• Operating Supply Voltage (typ): 3.3V
• Operating Temperature (min): -25C
• Operating Temperature (max): 85C
• Package Type: MMC
• Mounting: Socket
• Pin Count: 7
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (max): 3.6V
• Programmable: Yes
• Lead Free Status / RoHS Status: Compliant

Revision 1.3
© 2005 SanDisk Corporation
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Functional Description
Flash-Independent Technology
Defect and Error Management
The MultiMediaCard and RS-MultiMediaCard contain a high level, intelligent subsystem
as shown by the block diagram in Figure 1-1. This intelligent (microprocessor) subsystem
provides many capabilities not found in other types of memory cards. These capabilities
include:
The 512-byte sector size of the MultiMediaCard and RS-MultiMediaCard is the same as
that in an IDE magnetic disk drive. To write or read a sector (or multiple sectors), the host
computer software simply issues a read or write command to the card. This command
contains the address. The host software then waits for the command to complete. The host
software does not get involved in the details of how the flash memory is erased,
programmed or read. This is extremely important as flash devices are expected to get more
and more complex in the future. Because the MultiMediaCard and RS-MultiMediaCard
uses an intelligent on-board controller, the host system software will not require changing
as new flash memory evolves. In other words, systems that support the SanDisk
MultiMediaCard/RS-MultiMediaCard today will be able to access future cards built with
new flash technology without having to update or change host software.
The SanDisk MultiMediaCard and RS-MultiMediaCard contain a sophisticated defect and
error management system. This system is analogous to the systems found in magnetic disk
drives and in many cases offers enhancements. For example, disk drives do not typically
perform a read after write to confirm the data is written correctly because of the
performance penalty that would be incurred. MultiMediaCards and RS-MultiMediaCards
do a read after write under margin conditions to verify that the data is written correctly. In
the rare case that a bit is found to be defective, the cards replace it with a spare bit within
the sector header. If necessary, the card will replace the entire sector with a spare sector.
This is completely transparent to the host and does not consume any user data space.
The card’s soft error rate specification is much better than the magnetic disk drive
specification. In the extremely rare case a read error does occur, a SanDisk
MultiMediaCard/RS-MultiMediaCard possesses innovative algorithms to recover the data.
This is similar to using retries on a disk drive but is much more sophisticated.
The last line of defense is to employ a powerful ECC to correct the data. If ECC is used to
recover data, defective bits are replaced with spare bits to ensure they do not cause any
future problems. These defect and error management systems coupled with the solid-state
construction give SanDisk MultiMediaCards and RS-MultiMediaCards unparalleled
reliability.
Host independence from details of erasing and programming flash memory
Sophisticated system for managing defects (analogous to systems found in magnetic
disk drives)
Sophisticated system for error recovery including a powerful error correction code
Power management for low power operation
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MultiMediaCard/RS-MultiMediaCard Product Manual
Chapter 1 – Introduction
03/22/05