Go Down

Topic: Arduino Uno Rev3 pinouts photo (Read 95 times) previous topic - next topic


Apr 16, 2013, 01:08 pm Last Edit: Apr 16, 2013, 01:11 pm by Testato Reason: 1

I've put the same photo on my website, with various annotations about what the abreviations

Hi Nick, on your website correct this
giving a reading between 0 (for 0V) and 1024 (for 5V) using the analogRead function

between 0 and 1023  ;)

- [Guida] IDE - http://goo.gl/ln6glr
- [Lib] ST7032i LCD I2C - http://goo.gl/GNojT6
- [Lib] PCF8574+HD44780 LCD I2C - http://goo.gl/r7CstH

Nick Gammon


there really is so many thing to learn....

I'm not sure where to post this, but here goes ...

Below is a modified photo of the Uno Rev3 board, with annotations about the extra meanings of some pins (not printed on the board):

I personally find that when trying to hook up I2C or SPI, I can never remember which pin is SDA and which is SCL. Hopefully this photo will help others to quickly connect up their systems.

Earlier boards are similar except that they don't have the ICSP header for programming the USB interface chip, and the extra SDA/SCL sockets for use with I2C.

I find that the pins on the ICSP header (on the right) are useful for grabbing an extra +5/Gnd combination if I need to power other devices (or for hooking up a multimeter or logic analyzer).


Hi Nick,
              To someone like me who only just took up the Arduino  and had my Uno for about 3 days, that printout is going to be very useful!!  All I have to do now is learn C? Well I'm getting there a few simple things, but lots to learn..

Open your mind! But not too far, your brains might fall out.
Also like Photography, model building and my 300+ Cacti and Succs.


Some great information here... I've been using Nick's guide at http://www.gammon.com.au/forum/?id=11637 to successfully bootload the ATMega328P-PU and get a sketch uploaded using an FTDI friend.  Thanks for making such clear instructions, Nick!

Jack, great excel-version pinout of the '328.  Is this pinout the same whether it's bootloaded at 8MHz (Lilypad) or 16MHz (using an external resonator)?


Nick Gammon

The speed won't affect anything except ... speed. Nor will the bootloader. That is just for getting new code on the board.


Hi Nick,

Nice work on this helpful graphic. To say nothing of all the other great info I use on your site.

May I use this image on the ArduinoInfo.Info WIKI? I'd also link back to your page...

Other, if you have time, please take a look at this beginning discussion of Timer Conflicts:

Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

Nick Gammon


I can never remember which pin is SDA and which is SCL

SCL = Simply Connect Last (at least on an Arduino 328)

SDA = Shouldbe Dhe Ather (The other)   ;)

Lol I came up with my own rule, but yours makes morse sense...

C before D.

Go Up