Teensy 2.0 Pinout Diagram
-------------------------
USB is on top in the diagram.
Inner columns are pin numbers, outer columns are port+bit pin name.
```
ground  GND      USB      VCC   +5v power
        B0 0            21 F0
        B1 1            20 F1
        B2 2            19 F4
        B3 3            18 F5
        B7 4            17 F6
SCL     D0 5            16 F7
SDA     D1 6            15 B6
        D2 7            14 B5
        D3 8            13 B4
        C6 9            12 D7
        C7 10           11 D6   Do not use pin D6 for scanning keyboard matrix
                                LED on pin D6 pulls voltage down and will always return low

BOTTOM EDGE (USB on top, pins from left to right)
PIN#    port+bit        function
23      D5
        VCC             5v power
        GND             ground
        RST             reset
22      D4

MIDDLE (below USB, pins from left to right)
PIN#    port+bit        function
24      E6
Ref
```

Teensy 2.0 pin assignment on https://www.pjrc.com/teensy/pinout.html
Teensy 2.0 pinout with pin numbers on http://www.pjrc.com/teensy/td_digital.html
Identifying and naming ports is useful when instantiating RowPorts and ColPorts.
Keybrd library was tested on Teensy 2.0
