To talk to the LED helper chip you'll need to use our Arduino Adafruit LED Backpack library from github.

To download you can visit the repository, or simply click on this button:

Rename the uncompressed folder Adafruit_LEDBackpack. Check that the Adafruit_LEDBackpack folder contains Adafruit_LEDBackpack.cpp and Adafruit_LEDBackpack.h Place the Adafruit_LEDBackpack library folder your arduinosketchfolder/libraries/ folder.

You may need to create the libraries subfolder if it's your first library. We also have a great tutorial on Arduino library installation at:

Rename the uncompressed folder Adafruit_GFX and check that the Adafruit_GFX folder contains Adafruit_GFX.cpp and Adafruit_GFX.h

Place the Adafruit_GFX library folder your arduinosketchfolder/libraries/ folder like you did with the LED Backpack library

It's not actually used for the 7-segment display, it's only for the matrix backpacks but it's still required by the library so please install it to avoid errors! Restart the IDE.

Run Test!

Once you've restarted you should be able to select the File->Examples->Adafruit_LEDBackpack->minimatrix16x8 example sketch. Upload it to your Feather as usual. You should see a basic test program that goes through a bunch of different routines.

Note that the normal "matrix16x8" demo wont work the way you want because the matrix alignment is different on the Feather!

Upload to your Arduino, and open up the Serial console at 9600 baud speed. You'll see a little light show demonstrating bitmaps, drawing lines, circles and squares, text scrolling and more!

Library Reference

For the 16x8 displays, our library essentially treats it like a grpahical display with 128 pixels


You can create the object with

Adafruit_8x16minimatrix matrix = Adafruit_8x16minimatrix();

There's no arguments or pins because the backpacks use the fixed I2C pins.
By default, the address is 0x70, but you can pass in the I2C address used when you initialize the display with begin

matrix.begin(0x70);  // pass in the address

Drawing with Adafruit GFX

Once you're happy that the matrix works, you can write your own sketches. The 16x8 matrix supports everything the Adafruit GFX library - drawing pixels, lines, rectangles, circles, triangles, roundrects, and small bitmaps. For more details check out the GFX page which will detail all of the GFX routines.

Writing Data

Don't forget to 'write' the data to the display with


That's what actually 'sets' the data onto the LEDs!

Other things!

  • setBrightness(brightness)- will let you change the overall brightness of the entire display. 0 is least bright, 15 is brightest and is what is initialized by the display when you start
  • blinkRate(rate) - You can blink the entire display. 0 is no blinking. 1, 2 or 3 is for display blinking.
Last updated on 2016-05-19 at 08.13.40 PM Published on 2016-05-20 at 01.45.19 PM