Spotlight on the SD Card Interface
Thanks to simplified design requirements and a serial interface, SD cards are popular with OEMs in industrial applications. The SD Card interface follows strict guidelines, taking guesswork out of the process and ensuring smooth, reliable operations.
SD Card Interface Basics
SD Cards are used for NAND flash storage in applications that use the Secure Digital, or SD interface. The SD card interface is strictly controlled by the Secure Digital Association, which set very specific rules regarding the physical interface itself and command protocols. Generally, OEMs who are considering using SD cards should become members of the Secure Digital Association so that they have ongoing access to all of the specifications of the group. Some information about SD card interfaces is only available to members of the group, and many OEMs find it helpful to have access to the latest developments regarding the SD cards they incorporate into their applications.
SD Card Operations
SD cards have intelligent controllers. These controllers manage the flash operations and allow data transfer between the host system and the card. Typically, data are transferred in blocks of 512 bytes. SD cards that are 2 Gbytes or less use FAT12 or FAT16 for file storage. Cards over 4 Gbytes use FAT32. Industrial grade SD cards have a voltage range of 2.7-3.3V, though lower voltage cards are available for consumer electronic devices. SD cards default to SD mode, but it is also possible to configure cards to use SPI for applications that need a slower, simpler bus protocol.
Industrial SD Cards
Both industrial and consumer SD cards are available. Industrial SD cards use SLC NAND flash for increased data security in demanding operating environments. Data retention of up to 10 years is possible with an industrial grade SD card. These cards include SMART technology that monitors a card’s operations and flags potential issues before failures can occur. Customization options for SD cards include pad printing, unique formatting, laser etching, and custom labeling.
If you have further questions about the SD card interface or using SD cards for flash memory in your industrial application, Delkin’s product team is ready to help. Contact us with your questions or to request a sample.