I’ve bought two Arduino SD Cards modules from DX.com and didn’t found any info for them – So I decided to try by my self.
Reading a bit about Arduino SD cards i found out that Arduino SD card uses SPI (Serial Peripheral Interface) to communicate with the SD Cards and with Arduino UNO (along with others – except Mega) those PINs are 11, 12 and 13.
SPI connections always have a master (usually a microcontroler) and a slave device. Typically there are three lines common to all devices (and this SD card reader to):
| MISO (Master In Slave Out) | The slave line for sending data to the master |
|---|---|
| MOSI (Master Out Slave In) | The master line for sending data to the peripherals |
| SCK (Serial Clock) | The clock pulses synchronize data transmissions generated by the master |
More info on the SPI, you can check the Arduino Documentation.
About the SD Card, must be FAT16 or FAT32 formated.
The YL-30 SD Card Reader
This SD Card reader – Arduino Compatible – has some perks. All the PINS must be connected, even the 3.3V and +5V.
The wiring will be as follows:
| YL-30 SD PINs | Arduino PINs |
|---|---|
| GND | GND |
| MISO | 12 |
| SCK | 13 |
| MOSI | 11 |
| CS | 4 (It’s custom to be PIN 4) |
| 3.3V | 3.3V |
| GND | GND |
| +5V | 5V |
Now, just insert a SD card a let’s start Arduino IDE and write the code from Arduino tutorials about SD Cards – The Code is for a Ethernet Shield with a onboard SD Card – but it works perfectly here.
After compiling and uploading the code to the Arduino, here’s the result (I have no files in the card):
And here’s the finished contraption:
