+-----+
     +----[PWR]-------------------| USB |--+
     |                            +-----+  |
     |        "GND/RST2" [ ][ ]            |
     |     "MOSI2/SCK2"  [ ][ ]"A5/SCL"[ ] |   C5 
     |        "5V/MISO2" [ ][ ]"A4/SDA"[ ] |   C4 
     |                            AREF [ ] |
     |                             GND [ ] |
     | [ ]"N/C"                "SCK/13"[ ] |   B5
     | [ ] IOREF              "MISO/12"[ ] |  "."
     | [ ] RST                "MOSI/11"[ ]~|  "."
     | [ ] 3V3   +---+              10 [ ]~|  "."
     | [ ] 5v    | A |               9 [ ]~|  "."
     | [ ] GND  -| R |-              8 [ ] |   B0
     | [ ] GND  -| D |-                    |
     | [ ] Vin  -| U |-              7 [ ] |   D7
     |          -| I |-              6 [ ]~|  "."
     | [ ] A0   -| N |-              5 [ ]~|  "."
     | [ ] A1   -| O |-              4 [ ] |  "."
     | [ ] A2    +---+         "INT1/3"[ ]~|  "."
     | [ ] A3                  "INT0/2"[ ] |  "."
     | [ ]"A4/SDA"RST SCK MISO   "TX>1"[ ] |  "."
     | [ ]"A5/SCL"[ ] [ ] [ ]    "RX<0"[ ] |   D0
     |            [ ] [ ] [ ]              |
     | "UNO_R3"   GND MOSI 5V   ___________|
     |_________________________|