The SparkFun SD/MMC Card Breakout (Part ID: BOB-12941) is a compact and versatile breakout board designed to simplify the integration of SD or MMC memory cards into electronic projects. It provides easy access to the pins of an SD card, enabling users to interface with microcontrollers, such as Arduino, for data storage and retrieval. This breakout board is ideal for applications requiring data logging, file storage, or multimedia playback.
The SD/MMC Card Breakout is designed to work seamlessly with standard SD and MMC cards. Below are the key technical details:
Parameter | Value |
---|---|
Manufacturer | SparkFun |
Part ID | BOB-12941 |
Supported Card Types | SD, SDHC, MMC |
Operating Voltage | 3.3V (logic level) |
Input Voltage Range | 3.3V to 5V (via onboard regulator) |
Communication Protocol | SPI (Serial Peripheral Interface) |
Dimensions | 1.0" x 1.0" (25.4mm x 25.4mm) |
The breakout board provides a standard 6-pin interface for SPI communication. Below is the pinout description:
Pin Name | Pin Number | Description |
---|---|---|
GND | 1 | Ground connection |
3.3V | 2 | 3.3V power supply for the SD card |
CS | 3 | Chip Select (active low) |
MOSI | 4 | Master Out Slave In (data input to the SD card) |
MISO | 5 | Master In Slave Out (data output from the SD card) |
SCK | 6 | Serial Clock for SPI communication |
3.3V
pin to a 3.3V power source. If using a 5V system, the onboard voltage regulator will step down the voltage for the SD card.CS
, MOSI
, MISO
, and SCK
pins to the corresponding SPI pins on your microcontroller.GND
pin is connected to the ground of your circuit.Below is an example of how to connect the SD/MMC Card Breakout to an Arduino UNO:
SD/MMC Breakout Pin | Arduino UNO Pin |
---|---|
GND | GND |
3.3V | 3.3V |
CS | Pin 10 |
MOSI | Pin 11 |
MISO | Pin 12 |
SCK | Pin 13 |
The following Arduino sketch demonstrates how to initialize the SD card and write data to a file:
#include <SPI.h>
#include <SD.h>
// Define the chip select pin for the SD card
const int chipSelect = 10;
void setup() {
// Initialize serial communication for debugging
Serial.begin(9600);
while (!Serial) {
; // Wait for the serial port to connect
}
Serial.println("Initializing SD card...");
// Check if the SD card is present and can be initialized
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present.");
// Don't proceed if the card is not initialized
while (1);
}
Serial.println("Card initialized.");
// Create or open a file on the SD card
File dataFile = SD.open("example.txt", FILE_WRITE);
// Check if the file opened successfully
if (dataFile) {
dataFile.println("Hello, SD card!"); // Write data to the file
dataFile.close(); // Close the file
Serial.println("Data written to file.");
} else {
Serial.println("Error opening file.");
}
}
void loop() {
// Nothing to do here
}
SD Card Initialization Fails
CS
pin is correctly defined in your code and connected to the microcontroller.File Not Opening or Writing
example.txt
).Data Corruption
Q: Can I use this breakout board with a 5V microcontroller?
A: Yes, the breakout board includes a voltage regulator to step down 5V to 3.3V. However, you may need a level shifter for the SPI lines to prevent damage to the SD card.
Q: What is the maximum storage capacity supported?
A: The breakout board supports SD and SDHC cards, typically up to 32GB. Larger cards may work but are not guaranteed.
Q: Can I use this breakout board for non-SPI communication?
A: No, this breakout board is designed specifically for SPI communication with SD/MMC cards.
Q: How do I know if the SD card is working?
A: Use the SD.begin()
function in your code to check if the card initializes successfully. If it fails, verify the connections and card format.
By following this documentation, you can effectively integrate the SparkFun SD/MMC Card Breakout into your projects for reliable data storage and retrieval.