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.
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This circuit features an Arduino Mega 2560 microcontroller interfaced with an OLED display, a DS1307 RTC module, a microSD card breakout, a pushbutton, and a blue LED. The Arduino handles data logging to the microSD card, displays information on the OLED, and reads real-time data from the RTC module, while the pushbutton and LED provide user interaction and status indication.
This circuit integrates multiple microcontrollers (Maple Mini STM32F1, nRF52840 ProMicro, and Arduino Pro Mini) to interface with various peripherals including an SSD1306 OLED display, an SD card module, and a Si4463 RF module. The circuit is designed for data acquisition, storage, and wireless communication, with power supplied through a USB Serial TTL module.
This circuit features an ESP32-C3 microcontroller interfaced with a Micro SD Card Module. The ESP32-C3 handles SPI communication with the SD card for data storage and retrieval, with specific GPIO pins assigned for MOSI, MISO, SCK, and CS signals.
This circuit consists of an Arduino UNO connected to an SD card module. The Arduino provides power and ground to the SD module and interfaces with it using SPI communication through digital pins D10 (CS), D11 (MOSI), D12 (MISO), and D13 (SCK). The setup is intended for reading from or writing to an SD card using the Arduino.
Multimedia applications, such as audio or video playback
Bootloading or firmware storage for microcontrollers
Portable data transfer between devices
Technical Specifications
The SD/MMC Card Breakout is designed to work seamlessly with standard SD and MMC cards. Below are the key technical details:
General Specifications
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)
Pin Configuration
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
Usage Instructions
Connecting the SD/MMC Card Breakout
Power Supply: Connect the 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.
SPI Interface: Connect the CS, MOSI, MISO, and SCK pins to the corresponding SPI pins on your microcontroller.
Ground: Ensure the GND pin is connected to the ground of your circuit.
Example Circuit with Arduino UNO
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
Example Code for Arduino
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
}
Best Practices
Use a level shifter if interfacing with a 5V microcontroller to avoid damaging the SD card.
Format the SD card to FAT16 or FAT32 before use.
Avoid removing the SD card while the system is powered on to prevent data corruption.
Use decoupling capacitors near the power pins for stable operation.
Troubleshooting and FAQs
Common Issues and Solutions
SD Card Initialization Fails
Ensure the SD card is properly inserted into the breakout board.
Verify the CS pin is correctly defined in your code and connected to the microcontroller.
Check the power supply voltage (3.3V) and ensure it is stable.
File Not Opening or Writing
Confirm the SD card is formatted to FAT16 or FAT32.
Ensure the file name is valid and follows the 8.3 filename convention (e.g., example.txt).
Data Corruption
Avoid removing the SD card while the system is powered on.
Use proper error handling in your code to detect and manage write failures.
FAQs
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.
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