Micro SD cards and microcontrollers go together like micro-peanutbutter-and-jelly: SD cards are inexpensive, durable, easy to find at any shop, come in many sizes and can plug into any computer using a common SD card reader. That makes them perfect for microcontroller storage and retrieval - whether it's images, fonts, GIFs, audio files, or sensor logs.

Wiring up SD cards when you're starting out is super easy - you just pick up one of our SPI-to-SD breakout boards, wire it to an SPI port and a chip select pin and with a little library work you're reading and writing files. That's all good and great but you may eventually find that your SD card project is a little...slow. Even with fast SPI ports, there's only one data pin, which can make it hard to stream large files fast.

If you've hit that limit, this breakout is designed to help - unlike our other adapter, it is not fixed for SPI usage, and can be used with SDIO hardware support. SDIO is a multi-pin data protocol (up to 4 data pins at once!) SDIO also tends to be able to be clocked faster than SPI. Of course, your speeds will vary depending on what microcontroller you hook it up to. When we used SDIO instead of SPI on CircuitPython with the SAMD51 Grand Central, we got a speed increase of about double when reading data off the card.

You will need to verify that your microntroller has SDIO support and you have SDIO firmware/library support as well. SDIO is usually available on higher end chips, and you may need to use a specific pin set. You can still use this for SPI mode, but it does not have level shifters so it's not for use with 5V microcontrollers.

For use with 3V power and logic microcontollers only! The SDIO pins are bi-directional, and we've never seen a 5V microcontroller with SDIO, so there's no level shifting or power regulator.

Comes with a bit of header so you can use in a breadboard. Doesn't come with the micro SD card itself!