MD5811-D256-V3Q18-X SanDisk, MD5811-D256-V3Q18-X Datasheet - Page 42

• Manufacturer Part Number: MD5811-D256-V3Q18-X
• Description: IC MDOC P3 256MB 48-TSOP
• Manufacturer: SanDisk

Specifications of MD5811-D256-V3Q18-X

• Format - Memory: FLASH
• Memory Type: FLASH - Nand
• Memory Size: 256M (32M x 8)
• Speed: 55ns
• Interface: Parallel
• Voltage - Supply: 2.5 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-TSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

7.1.1
The TrueFFS driver is integrated into all major OSs, including Symbian, Palm OS, Pocket PC
2002/3, Smartphone 2002/3, Windows CE/NT, Linux (various kernels), Nucleus, and others. For a
complete listing of all available drivers, please refer to M-Systems’ website, www.m-sys.com. It is
advised to use the latest driver versions that can be downloaded from the website.
7.1.2 TrueFFS Software Development Kit (SDK)
The basic TrueFFS Software Development Kit (SDK) developer guide provides the source code for
the TrueFFS driver. It can be used in an OS-less environment or when special customization of the
driver is required for proprietary OSs.
When using Mobile DiskOnChip P3 as the boot replacement device, TrueFFS SDK also
incorporates in its source code the boot software that is required for this configuration (this package
is also available separately). Please refer to the DiskOnChip Boot Software Development Kit (BDK)
developer guide for further information on using this software package.
Note: Mobile DiskOnChip P3 is supported by TrueFFS 6.1 and above.
7.1.3
TrueFFS accesses the flash memory within Mobile DiskOnChip P3 through an 8KB window in the
CPU memory space. TrueFFS provides block device API by using standard file system calls,
identical to those used by a mechanical hard disk, to enable reading from and writing to any sector
on Mobile DiskOnChip P3. This makes Mobile DiskOnChip P3 compatible with any file system
and file system utilities, such as diagnostic tools and applications. When using the Flash Allocation
Table (FAT) file system, the data stored on Mobile DiskOnChip P3 uses the FAT-16 file system.
Note: Mobile DiskOnChip P3 is shipped unformatted and contains virgin media.
7.1.4
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. 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.
7.1.5
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 array vendor. The erase cycle limit applies to
each individual erase block in the flash device. In Mobile DiskOnChip P3, the erase cycle limit of
the flash is 100,000 erase cycles. This means that after approximately 100,000 erase cycles, the
erase block begins to make storage errors at a rate significantly higher than the error rate that is
typical to the flash.
In a typical application, and especially if a file system is used, specific pages are constantly updated
(e.g., the page/s 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.
39
Built-In Operating System Support
File Management
Bad Block Management
Wear-Leveling
Data Sheet, Rev. 0.3
Mobile DiskOnChip P3
93-SR-009-8L