The Downloads section is for microcontroller boards which incorporate CircuitPython compatibility. If you have a Single Board Linux computer, see the Adding to Blinka page.

Image Location

Once you have your images prepared, you will want to place them into the three folders inside assets/images/boards as follows:

  1. The Original Sized image should be placed into the original folder.
  2. The Larger of the two resized images should be placed into the large folder.
  3. The Smaller of the two resized images should be placed into the small folder.

All three images should have the same filename.

Markdown File

The markdown file contains all of the information used for the board. To create a Markdown file for your board, go into the _boards folder and make a duplicate of the file.

You will want to rename the duplicate to something like to match your image files. For instance, if your images were named feather_m4_express.jpg, you would want to use

Open up the new markdown file in your favorite text editor. This should be a text editor like Windows notepad and not a word processor such as Microsoft Word because word processors add extra data that will not work well with the Markdown file format.

We'll start with the header section and go line by line to make sure you have the correct information added. The header section always starts with three hyphen characters and ends with three hyphen characters. You can always look at the other Markdown files for examples too. We're going to take a look at the Feather M4 Express file.

layout: download
board_id: "feather_m4_express"
title: "Feather M4 Express Download"
name: "Feather M4 Express"
manufacturer: "Adafruit"
board_url: ""
board_image: "feather_m4_express.jpg"
date_added: 2019-3-8
family: atmel-samd
bootloader_id: feather_m4
  - Feather-Compatible
  - Battery Charging
  - Breadboard-Friendly

This feather is powered by the ATSAMD51J19 -  with its 120 MHz Cortex M4 with floating point support and 512 KB Flash and 192 KB RAM. Your code will zig and zag and zoom, and with a bunch of extra peripherals for support, this will for sure be your favorite new chipset.

And best of all, it's a Feather - so you know it will work with all our FeatherWings! What a great way to quickly get up and running.

The most exciting part of the Feather M4 is that while you can use it with the Arduino IDE - and it's bonkers fast when you do, we are shipping it with CircuitPython on board. When you plug it in, it will show up as a very small disk drive with on it. Edit with your favorite text editor to build your project using Python, the most popular programming language. No installs, IDE or compiler needed, so you can use it on any computer, even ChromeBooks or computers you can't install software on. When you're done, unplug the Feather and your code will go with you.

The Feather M4 Express uses the extra space left over to add a Mini NeoPixel, 2 MB SPI Flash storage and a little prototyping space. You can use the SPI Flash storage like a very tiny hard drive. When used in CircuitPython, the 2 MB flash acts as storage for all your scripts, libraries and files. When used in Arduino, you can read/write files to it, like a little datalogger or SD card, and then with our helper program, access the files over USB.

Easy reprogramming: the Feather M4 comes pre-loaded with the UF2 bootloader, which looks like a USB storage key. Simply drag firmware on to program, no special tools or drivers needed! It can be used to load up CircuitPython or Arduino IDE (it is bossa-compatible).

Comes fully assembled and tested, with the UF2 USB bootloader. We also toss in some headers so you can solder it in and plug into a solderless breadboard.

## Technical details

* Measures 2.0" x 0.9" x 0.28" (50.8 mm x 22.8 mm x 7 mm) without headers soldered in
* Light as a (large?) feather - 5 grams
* ATSAMD51 32-bit Cortex M4 core running at 120 MHz, 32-bit, 3.3 V logic and power
* Floating point support with Cortex M4 DSP instructions
* 512 KB flash, 192 KB RAM
* 2 MB SPI FLASH chip for storing files and CircuitPython code storage.
* 32.768 kHz crystal for clock generation & RTC
* 3.3 V regulator with 500 mA peak current output
* USB native support, comes with USB bootloader and serial port debugging
* Built in crypto engines with AES (256 bit), true RNG, Pubkey controller
* 21x GPIO pins with following capabilities:
  * Dual 1 MSPS 12 bit true analog DAC (A0 and A1) - can be used to play 12-bit stereo audio clips
  * Dual 1 MSPS 12 bit ADC (6 analog pins some on ADC1 and some on ADC2)
  * 6x hardware SERCOM - Native hardware SPI, I2C and Serial all available
  * 16x PWM outputs - for servos, LEDs, etc
  * I2S input and output
  * 8-bit Parallel capture controller (for camera/video in)
* Built in 100 mA lipoly charger with charging status indicator LED
* Pin #13 red LED for general purpose blinking
* Power/enable pin
* 4 mounting holes
* Reset button

## Tutorials

* [Feather M4 Express Overview](

## Purchase

* [Adafruit](
* [Digi-Key](



Leave this set to download since we're on the downloads page


This should be the name of the board for example "feather_m4_express".


This is the page title and should be more descriptive and end with the word Download. For example "Feather M4 Express Download".


This is the name of the board and should be the same as Title but without the word Download. For example "Feather M4 Express".


The name of the board manufacturer. For example "Adafruit".


This is a full URL that the use to view the product information for the board. For example "".


This is the filename only for the image you created. The path for the appropriate sized will automatically be generated. For instance "feather_m4_express.jpg".


This is the date the board was added to CircuitPython, or if you're not sure, you can just use the current date. The format is YYYY-M-D with a 4-digit year, 1 or 2 digit month, and 1 or 2 digit day. In this case, the date it was added was March 8, 2019 or "2019-3-8".


This is the bootloader family and should correspond to one of the values in here such as atmel-samd.

    "bootloaders": {
        "nrf52840": {
            "version": "0.7.0"
        "atmel-samd": {
            "version": "v3.15.0"
        "esp32s2": {
            "version": "0.16.0"
        "esp32s3": {
            "version": "0.16.0"
        "esp32c3": {},
        "esp32": {},
        "stm": {},
        "cxd56": {},
        "mimxrt10xx": {},
        "raspberrypi": {},
        "broadcom": {},
        "litex": {},
        "silabs": {}


This is the bootloader ID and should be included, if available, on bootloader certain bootloader families that have a version number in the file above. To find the ID, you can look in the following repositories:


This can optionally be included in order to hide your board by setting it to false. Omitting this value or setting it to true will display your board. The value should be true or false.


This is a list with features that the board has such as Battery Charging, Bluetooth, WiFi, etc. Items in this list are preceded by two spaces, a hyphen character, and another space. Features should be limited to the items in this list and spelled exactly the same:

  • Speaker
  • Solder-Free Alligator Clip
  • Feather-Compatible
  • Battery Charging
  • Display
  • Wi-Fi
  • Bluetooth/BTLE
  • Robotics
  • LoRa/Radio
  • GPS
  • USB-C
  • Breadboard-Friendly
  • Arduino Shield Compatible
  • Xiao / QTPy Form Factor


The body is more free form and should include at least one paragraph for a description of the board. This is often copied from a product page.

Purchase Section

If a board is available for purchase, it should include a Purchase section with one or more links. The link text should be the name of the website it linked to such as Amazon, Adafruit, AliExpress, etc.

Learn More Section

This section is more commonly found on pages where the board is not yet available for purchase. This should include informational links about the board. The link text should be the name of the website it linked to such as GitHub, NVIDIA, etc.

Submit a Pull Request

Now that you have your changes made, go ahead and commit your code to Github and submit a Pull Request. It will be reviewed and if it looks good, it will be merged in.

This guide was first published on Jul 24, 2019. It was last updated on Jul 24, 2019.

This page (Adding to Downloads) was last updated on Jul 18, 2019.

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