How to use SD card

I just want some extra information about the pins the SD card uses specifically on arduino/genuino Uno.

1)Why i must use pins 11,12,13 and just set pin 10 as output without connecting it with any components? 2)Also does each pin need to be connected to a specific pin on the SD card?(i.e does MOSI on SD card need to be always connected to pin 11?) :confused:

1) Those are the hardware SPI pins. pin 10 must be configured as an output for SPI master mode, whether or not you use it as a slave-select line.

2) Yes the pin assignments are fixed in silicon, however if your Arduino is 5V you must use level-shifting circuitry as SDcards are 3.3V only.

Thanks a lot :slight_smile: :slight_smile:
However, I watched a video that he used a SD card reader that it had the choice of using 5V or 3.3V. I mean it’s ok right?

SDcards are 3.3V maximum always.

Some SDcard breakout boards may have built-in level shifters and 3.3V regulators on them, saving you the effort of providing them.

If you have just an SDcard socket on a breakout board, no other components, its 3.3V or a toasted SDcard.

HAHAHAH thanks a lot :)

Or use a 3.3v based Arduino. ;)