GEMMA M0 boards can run CircuitPython — a different approach to programming compared to Arduino sketches. In fact, CircuitPython comes factory pre-loaded on GEMMA M0. If you’ve overwritten it with an Arduino sketch, or just want to learn the basics of setting up and using CircuitPython, this is explained in the Adafruit GEMMA M0 guide.
Below is CircuitPython code that works similarly (though not exactly the same) as the Arduino sketch shown on a prior page. To use this, plug the GEMMA M0 into USB…it should show up on your computer as a small flash drive…then edit the file “code.py” with your text editor of choice. Select and copy the code below and paste it into that file, entirely replacing its contents (don’t mix it in with lingering bits of old code). When you save the file, the code should start running almost immediately (if not, see notes at the bottom of this page).
If GEMMA M0 doesn’t show up as a drive, follow the GEMMA M0 guide link above to prepare the board for CircuitPython.
This code requires two additional libraries be installed:
- adafruit_circuitpython_ht16k33
- adafruit_bus_device
If you’ve just reloaded the board with CircuitPython, create the “lib” directory and then download the Adafruit CircuitPython Bundle.
# SPDX-FileCopyrightText: 2014 Phil Burgess for Adafruit Industries # SPDX-FileCopyrightText: 2018 Phil Burgess for Adafruit Industries # # SPDX-License-Identifier: MIT # # Trinket/Gemma + LED matrix backpack jewelry. Plays animated # sequence on LED matrix. Press reset button to display again. import time import adafruit_ht16k33.matrix import board import busio as io import touchio touch = touchio.TouchIn(board.D1) i2c = io.I2C(board.SCL, board.SDA) matrix = adafruit_ht16k33.matrix.Matrix8x8(i2c) # pixels initializers x_pix = y_pix = 8 x = y = 0 matrix.fill(0) matrix.show() # seconds to pause between frames frame_delay = [.25, .25, .25, .25, .25, .25, .25, .25, .25, .25] # counter for animation frames frame_count = 0 # repeat entire animation multiple times reps = 255 rep_count = reps # animation bitmaps animation = [ # frame 1 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 0, 0, 0, 0, 1], [1, 1, 0, 0, 0, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 2 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 1, 1, 1, 1, 0, 1], [1, 0, 1, 1, 1, 1, 0, 1], [1, 1, 0, 0, 0, 0, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 3 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 0, 0, 0, 0, 1], [1, 1, 0, 0, 0, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 4 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 1, 1, 1, 1, 0, 1], [1, 0, 1, 1, 1, 1, 0, 1], [1, 1, 0, 0, 0, 0, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 5 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 0, 0, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 6 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 0, 0, 1, 1, 0, 0, 1], [1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 0, 1, 1, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 7 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 1, 1, 1, 1, 0, 1], [0, 0, 0, 1, 1, 0, 0, 0], [1, 0, 1, 1, 1, 1, 0, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 0, 1, 1, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 8 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1], [0, 0, 0, 1, 1, 0, 0, 0], [1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 0, 1, 1, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], # frame 9 [[1, 1, 1, 1, 1, 1, 1, 1], [1, 0, 1, 1, 1, 1, 0, 1], [0, 0, 0, 1, 1, 0, 0, 0], [1, 0, 1, 1, 1, 1, 0, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 0, 1, 1, 0, 1, 1], [1, 1, 1, 0, 0, 1, 1, 1], [1, 1, 1, 1, 1, 1, 1, 1]], ] # # run until we are out of animation frames # use Gemma's built-in reset button or switch to restart # # populate matrix while True: if frame_count < len(animation) and rep_count >= 0: for x in range(x_pix): for y in range(y_pix): matrix.pixel(x, y, animation[frame_count][x][y]) # next animation frame frame_count += 1 # show animation matrix.show() # pause for effect time.sleep(frame_delay[frame_count]) else: matrix.fill(0) matrix.show() time.sleep(.1) # track repitions rep_count -= 1 # play it again frame_count = 0 # A0/D1 pin has been touched # reset animation if touch.value: frame_count = 0 rep_count = reps
Page last edited January 21, 2025
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