Product manual

Introduction to the Industrial Grade SD Card

1.5.4. Endurance

SanDisk Industrial Grade SD Cards have an endurance specification for each sector of 600,000 writes typical

(reading a logical sector is unlimited). This far exceeds what is typically required in nearly all applications of SD

cards. For example, even very heavy use of the Industrial Grade SD Card in cellular phones, personal

communicators, pagers and voice recorders will use only a fraction of the total endurance over the typical device’s

lifetime. For instance, it would take over 10 years to wear out an area on the Industrial Grade SD Card on which a

file of any size (from 512 bytes to maximum capacity) was rewritten 3 times per hour, 8 hours a day, 365 days per

year.

With typical applications, the endurance limit is not of any practical concern to the vast majority of users.

1.5.5. Wear Leveling

Wear-leveling is an intrinsic part of the Erase Pooling functionality of SD using NAND memory. The Industrial

Grade SD Card’s Wear Level command is supported as a NOP operation to maintain backward compatibility with

existing software utilities.

1.5.6. Using the Erase Command

The Erase (sector or group) command provides the capability to substantially increase the write performance of the

Industrial Grade SD Card. Once a sector has been erased using the Erase command, a write to that sector will be

much faster. This is because a normal write operation includes a separate sector erase prior to write.

1.5.7. Automatic Sleep Mode

A unique feature of the SanDisk Industrial Grade SD Card (and other SanDisk products) is automatic entrance and

exit from sleep mode. Upon completion of an operation, the Industrial Grade SD Card will enter the sleep mode to

conserve power if no further commands are received within 5msec. The host does not have to take any action for

this to occur. In most systems, the Industrial Grade SD Card is in sleep mode except when the host is accessing it,

thus conserving power.

When the host is ready to access the Industrial Grade SD Card and it is in sleep mode, any command issued to the

card will cause it to exit sleep and respond.

1.5.8. Hot Insertion

Support for hot insertion will be required on the host but will be supported through the connector. Connector

manufacturers will provide connectors that have power pins long enough to be powered before contact is made with

the other pins. Please see connector data sheets for more details. This approach is similar to that used in PCMCIA

and MMCA devices to allow for hot insertion.