What Are Secure Digital Card Specifications?
Secure Digital cards, or SD cards, are a specific type of non-volatile storage that was developed by the Secure Digital Association, or SDA. SD cards are manufactured by a number of different companies, but the SDA issues strict guidelines that dictate the features that the cards must have and how they must be designed and constructed. Secure Digital card specifications exist to ensure that OEMs and developers who use SD cards in their devices know exactly what they are getting and experience seamless compatibility with all of their SD cards, regardless of who actually made them.
SDA and Secure Digital Card Specification Rules
In order to have full access to all of the rules associated with manufacturing SD cards, companies must join the SDA, and there are over 1,000 companies who are members of the SDA. There is a membership fee required, as well as paperwork for licensing purposes. Before you can access any SDA intellectual property for licensing or the full SD card specifications, you must execute a membership agreement that is accepted by the SDA.
Although the full version of the card specifications is only available to members, there is a version of the specifications called the SD Simplified Specifications. These are simplified versions of some of the rules for making SD cards that are available without membership in the SDA.
Secure Digital Card Simplified Specification Usage
SD card simplified specifications cover specs for certain SD card parts. These are the simplified specifications that are available:
- Physical layer simplified specification
- UHS-II simplified addendum
- NFC interface simplified addendum
- ASSD extension simplified specification
- SD host controller simplified specification
- SD extensions API simplified specification
- SDIO simplified specification
- SDIO Bluetooth type A simplified specification
- iSDIO simplified specification
- Wireless LAN simplified addendum
Although these specifications are available to non-SDA members, they are not intended to be implemented by non-members without the appropriate licensing or memberships. As they are only portions of the full SD card specifications, they are not sufficient to allow SD card manufacturing.