MD2534-D2G-X-P SanDisk, MD2534-D2G-X-P Datasheet - Page 35

• Manufacturer Part Number: MD2534-D2G-X-P
• Description: IC MDOC H3 2GB FBGA
• Manufacturer: SanDisk

Specifications of MD2534-D2G-X-P

• Format - Memory: FLASH
• Memory Type: FLASH - Nand
• Memory Size: 2G (256M x 8)
• Interface: Parallel
• Voltage - Supply: 1.65 V ~ 1.95 V, 2.5 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 115-TFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Speed: -

proprietary OSs. The DOC driver SDK is used also for utilizing mDOC H3 as the boot device.
TrueFFS 7.1 Software Development Kit (TrueFFS 7.1 SDK) provides the DOC driver code,
bundled with the TrueFFS code needed to support earlier mDOC technologies (such as G3, G4
and H1) as well.
6.3.1
DOC driver accesses the flash memory within mDOC H3 through either 8KB or 128KB window
in the CPU memory space, depending on the mDOC H3 configuration. mDOC driver provides
block device API by using standard file system calls, identical to those used for a hard disk, to
enable reading from and writing to mDOC H3. This makes mDOC H3 compatible with any file
system and file system utilities, such as diagnostic tools and applications.
Note: mDOC H3 is shipped unformatted and contains virgin media.
6.3.2
Since NAND flash is an imperfect storage media, it can contain bad blocks that cannot be used
for storage because of their high error rates. Embedded TrueFFS automatically detects and maps
out bad blocks upon system initialization, ensuring that they are not used for storage. This
management process is completely transparent to the user, who is unaware of the existence and
location of bad blocks, while remaining confident of the integrity of data stored.
6.3.3
Flash memory can be erased a limited number of times. This number is called the erase cycle
limit, or write endurance limit, and is defined by the flash device vendor. The erase cycle limit
applies to each individual erase block in the flash device.
In a typical application, and especially if a file system is used, specific pages are constantly
updated (e.g., the pages that contain the FAT, registry, etc.). Without any special handling, these
pages would wear out more rapidly than other pages, reducing the lifetime of the entire flash.
To overcome this inherent deficiency, Embedded TrueFFS uses msystems’ patented wear-
leveling algorithm. This wear-leveling algorithm ensures that consecutive writes of a specific
sector are not written physically to the same page in the flash. This spreads flash media usage
evenly across all pages, thereby maximizing flash lifetime.
Dynamic Wear-Leveling
Embedded TrueFFS uses statistical allocation to perform dynamic wear-leveling on newly written
data. This means that new data will be written to flash units which are less worn out.
Static Wear-Leveling
Areas on the flash media may contain static files, characterized by blocks of data that remain
unchanged for very long periods of time, or even for the whole device lifetime. If wear-leveling
were only applied on newly written pages, static areas would never be cycled. This limited
application of wear-leveling would lower life expectancy significantly in cases where flash
memory contains large static areas. To overcome this problem, Embedded TrueFFS forces data
transfer in static areas as well as in dynamic areas, thereby applying wear-leveling to the entire
media.
35
File Management
Bad-Block Management
Wear-Leveling
Data Sheet (Preliminary) Rev. 0.2
mDOC H3 Embedded Flash Drive
92-DS-1205-10