title: which pins should i take for i2c on arduino uno
body: <p>I am trying to create an i2c communication bus with an arduino UNO.</p>
  
  <p>i2c requires SDA and SDL pins. I see on arduino UNO there is twice SDA and SDL:</p>
  
  <p>The 2 first pins side to usb connector are SDA/SCL according to documentation.</p>
  
  <p>And the documentation says A4 and A5 pins can also be SDA/SCL</p>
  
  <p>So i do not understand which pins i can use.</p>
  
  <p><a href="https://i.stack.imgur.com/sjZNV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sjZNV.png" alt="enter image description here"></a></p>
  
  <p>Thanks</p>