Welcome to the first in a series of posts on SDIO architecture. This first post is designed to give you a basic overview. It assumes little to no prior knowledge. If you already know the basics, pass this blog along to a colleague and join us next week for a more technical post.

Hear the term SD and you probably think immediately of the tiny memory cards. Your smartphone may even use them for extra storage.

The same basic technology that allows your digital camera to save gigabytes of images can also allow you to easily add WiFi, GPS, and other technologies to your embedded device. There’s a more advanced type of SD card that provides support for those and other types of devices. It’s called SDIO, short for Secure Digital Input Output.

The SDIO slot is the same size as a regular SD slot. The cards measure just 50 millimeters long by 24 millimeters wide by 2.1 millimeters thick (1.25 inches by 1 inch by .1 inch). They provide an incredibly lightweight means for adding devices.

Despite the small form factor, SDIO is fast. The high performance host controller from BSQUARE, for example, allows WiFi data transfer rates of greater than 10 Mbps.

SDIO also offers a number of other advantages other methods of adding functionality to your device. While both SDIO and USB allow you to take your wireless transceiver off your main chip, the SDIO approach involves less hardware, uses less power, and adds less cost.

Just be aware that while SD memory cards have universal support, SDIO devices typically require drivers that are specific to the device they’re used in. For example, a SDIO WiFi card would probably require two different drivers for two different embedded devices.

Next week we’ll talk about the differences between SD and MMC cards.

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Raymond Yip
Senior Software Engineer
Professional Engineering Services
BSQUARE Corporation | Contact Me!