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.
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.
3.3 V power input for the microSD card breakout; Adafruit warns that 5 V or VBAT will damage the card.
Common ground for power and logic.
Card-detect signal; connected to GND internally when no card is inserted and pulled up to 3V through 4.7 kΩ when a card is inserted.
SPI clock input to the SD card.
SPI serial data out from the SD card to the microcontroller.
SPI serial data input from the microcontroller to the SD card.
SPI chip-select input; pull low to start an SPI transaction.
SDIO bidirectional command/information signal between microcontroller and SD card.
SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D0.
SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D1.
SDIO bidirectional data line; Adafruit identifies the silkscreen legend as DAT2.
SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D3.
| Pin | Position | Type | Function | Voltage |
|---|---|---|---|---|
| 3V | power | 3.3 V power input for the microSD card breakout; Adafruit warns that 5 V or VBAT will damage the card. | 3.3V only | |
| GND | ground | Common ground for power and logic. | 0V | |
| DET | digital | Card-detect signal; connected to GND internally when no card is inserted and pulled up to 3V through 4.7 kΩ when a card is inserted. | 3V logic | |
| CLK / SCK | spi | SPI clock input to the SD card. | 3V logic |
SPI · 3.3V only · 0V
Verify supply voltage and logic levels before powering up.
Module pins: 3V, GND, CLK / SCK, SO / MISO, SI / MOSI, CS. Schematik maps them to your board in the app.
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| SO / MISO | spi | SPI serial data out from the SD card to the microcontroller. | 3V logic |
| SI / MOSI | spi | SPI serial data input from the microcontroller to the SD card. | 3V logic only |
| CS | spi | SPI chip-select input; pull low to start an SPI transaction. | 3V logic only |
| CMD | sdio | SDIO bidirectional command/information signal between microcontroller and SD card. | 3V logic |
| D0 | sdio | SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D0. | 3V logic |
| D1 | sdio | SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D1. | 3V logic |
| DAT2 | sdio | SDIO bidirectional data line; Adafruit identifies the silkscreen legend as DAT2. | 3V logic |
| D3 | sdio | SDIO bidirectional data line; Adafruit identifies the silkscreen legend as D3. | 3V logic |