Feather ASCII art pinout

Posted on August 31, 2018

Every time I design a FeatherWing, there are two things that bug me:

I’d like to have a Feather pinout that I can print out and mark up.
Every Feather has its own naming scheme for the pins, especially for the GPIO pins on the 12-pin header.

So, I put together a simple ASCII art diagram of the Feather pinout:

     +-------------------+
     | O               O |
     |                   |
~RST | o                 |
3V3  | o                 |
AREF | o                 |
GND  | o                 |
A0   | o               o | VBAT
A1   | o               o | EN
A2   | o               o | VUSB
A3   | o               o | F6
A4   | o               o | F5
A5   | o               o | F4
SCK  | o               o | F3
MOSI | o               o | F2
MISO | o               o | F1
RX   | o               o | F0
TX   | o               o | SCL
FREE | o               o | SDA
     |                   |
     | O               O |
     +-------------------+

I tried to use the names from the Feather specification, when possible. Sometimes the specification isn’t consistent: for example, it refers to the USB power pin both as VUSB and VBUS. I thought VUSB was clearer.

The one case in which no pin numbering scheme is given at all is the seven GPIO pins on the 12-pin header. Each Feather numbers these with the pin numbers used by its microcontroller, but they vary between one microcontroller and another. This makes it hard to refer to a pin generically on a FeatherWing, which could be used with any Feather. So, I numbered these pins F0 to F6. (“F” is for “Feather”, and to distinguish it from the microcontroller-specific pin numbers.)