If your microcontroller doesn’t provide any storage options, ourMicroSD breakout can help! The breakout allows you to connect MicroSD storage to your 3.3V microcontroller in fast SDIO mode or simple (but slower) SPI mode, with the flexibility to solder wires, headers and more, alongside M2.5 mounting options, underside soldering pads, power LED and cuttable configuration traces!

Each pin from the MicroSD slot is broken out toclearly labelled 2.54mm-spaced pads. You cansolderwhatever you like to these, such as theincluded 9-pin 2.54mm header strip(great forbreadboardusage), someprototyping wire, or even an9-way 2.54mm terminal block.

If you’re soldering wires, consider using theunderside solder pads. We added these because we know just how tricky it is to de-solder and re-solder a wire from a pad hole. With the underside pads, it’s much, much easier to re-work and re-use.

On the underside of the board, you’ll find twocuttable traces. One disables the onboard LED (if you’re not into the blinky life) and the other disables the pullups (just in case your dev board has pullups on the pins you’re using already).

We also usedM2.5 mounting holesas they’re a popular size with easy-to-source fixings…and because we despise fiddly M2 fixings.

SDIO or SPI Mode?

You can choose to run this in SDIO mode or SPI mode:

• SDIO mode: requires more pins but has less CPU overhead and is much quicker as it’s sending more data per cycle.
  • Compatibility: Not all microcontrollers support SDIO (they need a dedicated, hardware-level SDMMC peripheral onboard).
• SPI mode: uses fewer pins and is overall a simpler method, but is slower than 4-bit more.
  • Compatibility: As long as your dev board has an SPI interface (pins), you should be able to use the breakout in SPI mode.

We provide example ESP32-S3 code for Arduino IDE for both of these modes in our resources section (below) for use with an ESP32-S3.

Key Features

Compact 3.3V MicroSD breakout to add storage to microcontroller projects

MicroSDpins broken outto clearly labelled 2.54mm pads

Underside solder padsfor easy wire soldering and re-work

Blue power LED for visual indication (can be disabled via cuttable trace)

Cuttable tracesto disable the onboard LED and/or the pullup resistors

M2.5 mounting holesforfiddly-freemounting

ENIG (Gold) PCB platingfor oxidation resistance and durability

9-pin 2.54mm male header stripincluded!

Board Layout

Resources

• Assembly guide
• 3D Model (STEP)

Example code (for Arduino IDE):

• ESP32-S3 SDIO example
• ESP32-S3 SPI example

Dimensions

Please note that the corner radius may vary due to the manual PCB finishing process

Package Contents

• 1x MicroSD Breakout
• 1x 9-pin 2.54mm male header strip