Note: Some pins are not connected on a standard Arduino Uno R3 but still listed so you can use them if you had a custom board. It might also be possible that your ISP header of the 16u2 is flipped 180 ...

All the project information is provided under the CC BY-NC-SA 3.0 license. On a related note we covered a Microcontroller cheat sheet which covers AVR devices and ISP pinouts.

All the project information is provided under the CC BY-NC-SA 3.0 license. On a related note we covered a Microcontroller cheat sheet which covers AVR devices and ISP pinouts.