Example Code for Arduino-SD Card Info Test
Last revision 2025/12/17
This article offers a comprehensive guide to testing SD card functionality with Arduino, featuring example code, wiring instructions, and troubleshooting advice to ensure users can successfully retrieve SD card information.
Software Preparation
How to install Library?
Open the sample sketch "CardInfo"in the Arduino IDE. As you can see, it include the SD library called SD.h, you could also download other open source library on the web.
Wiring Diagram

| SDmodule | Arduino |
|---|---|
| MISO | D12 |
| SCK | D13 |
| SS chipSelect | D4 |
| MOSI | D11 |
| GND | GND |
| VCC | 5V |
Different Boards may have different SPI pin map, please check the datasheet of your controller.
Other Preparation Work
On the Ethernet Shield, CS is pin 4. It's set as an output by default. Note that even if it's not used as the CS pin, the hardware SS pin (10 on most Arduino boards, 53 on the Mega) must be left as an output or the SD library functions will not work. Change pin 10 to 53 on a mega.
Sample Code
/*
SD card test
This example shows how use the utility libraries on which the'
SD library is based in order to get info about your SD card.
Very useful for testing a card when you're not sure whether its working or not.
The circuit:
* SD card attached to SPI bus as follows:
** MOSI - pin 11 on Arduino Uno/Duemilanove/Diecimila
** MISO - pin 12 on Arduino Uno/Duemilanove/Diecimila
** CLK - pin 13 on Arduino Uno/Duemilanove/Diecimila
** CS - depends on your SD card shield or module.
Pin 4 used here for consistency with other Arduino examples
created 28 Mar 2011
by Limor Fried
modified 9 Apr 2012
by Tom Igoe
*/
// include the SD library:
#include <SD.h>
// set up variables using the SD utility library functions:
Sd2Card card;
SdVolume volume;
SdFile root;
// change this to match your SD shield or module;
// Arduino Ethernet shield: pin 4
// Adafruit SD shields and modules: pin 10
// Sparkfun SD shield: pin 8
const int chipSelect = 4;
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
Serial.print("\nInitializing SD card...");
// On the Ethernet Shield, CS is pin 4. It's set as an output by default.
// Note that even if it's not used as the CS pin, the hardware SS pin
// (10 on most Arduino boards, 53 on the Mega) must be left as an output
// or the SD library functions will not work.
pinMode(10, OUTPUT); // change this to 53 on a mega
// we'll use the initialization code from the utility libraries
// since we're just testing if the card is working!
if (!card.init(SPI_HALF_SPEED, chipSelect)) {
Serial.println("initialization failed. Things to check:");
Serial.println("* is a card is inserted?");
Serial.println("* Is your wiring correct?");
Serial.println("* did you change the chipSelect pin to match your shield or module?");
return;
} else {
Serial.println("Wiring is correct and a card is present.");
}
// print the type of card
Serial.print("\nCard type: ");
switch(card.type()) {
case SD_CARD_TYPE_SD1:
Serial.println("SD1");
break;
case SD_CARD_TYPE_SD2:
Serial.println("SD2");
break;
case SD_CARD_TYPE_SDHC:
Serial.println("SDHC");
break;
default:
Serial.println("Unknown");
}
// Now we will try to open the 'volume'/'partition' - it should be FAT16 or FAT32
if (!volume.init(card)) {
Serial.println("Could not find FAT16/FAT32 partition.\nMake sure you've formatted the card");
return;
}
// print the type and size of the first FAT-type volume
uint32_t volumesize;
Serial.print("\nVolume type is FAT");
Serial.println(volume.fatType(), DEC);
Serial.println();
volumesize = volume.blocksPerCluster(); // clusters are collections of blocks
volumesize *= volume.clusterCount(); // we'll have a lot of clusters
volumesize *= 512; // SD card blocks are always 512 bytes
Serial.print("Volume size (bytes): ");
Serial.println(volumesize);
Serial.print("Volume size (Kbytes): ");
volumesize /= 1024;
Serial.println(volumesize);
Serial.print("Volume size (Mbytes): ");
volumesize /= 1024;
Serial.println(volumesize);
Serial.println("\nFiles found on the card (name, date and size in bytes): ");
root.openRoot(volume);
// list all files in the card with date and size
root.ls(LS_R | LS_DATE | LS_SIZE);
}
void loop(void) {
}
Result
If your SD card is good and wiring is correct, open the Arduino IDE serial monitor, then you can see your SD card information. Or you might get this warn shown in the right picture.
The pinout is fully compatible with the DFRobot IO Expansion Shield V5.
Was this article helpful?
