Adafruit Qualia ESP32-S3 Instrukcja użytkownika

Adafruit Qualia ESP32-S3 for RGB-666

Displays

Created by Melissa LeBlanc-Williams

https://learn.adafruit.com/adafruit-qualia-esp32-s3-for-rgb666-displays

Last updated on 2023-10-20 10:53:17 AM EDT

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Table of Contents

Overview

Pinouts

• Microcontroller and WiFi

• 40-Pin Display Connector

• IO Expander

• Stemma QT Connector

• Reset and Boot0 Pins

• Debug Pin

• SPI Pins

• Analog Connector/Pins

• Buttons

• Backlight Jumpers

• IO Expander Address Jumpers

• Parallel Interface Jumpers

CircuitPython

• CircuitPython Quickstart

The CIRCUITPY Drive

• Boards Without CIRCUITPY

CircuitPython Pins and Modules

• CircuitPython Pins

• import board

• I2C, SPI, and UART

• What Are All the Available Names?

• Microcontroller Pin Names

• CircuitPython Built-In Modules

7

11

16

19

20

Installing the Mu Editor

• Download and Install Mu

• Starting Up Mu

• Using Mu

Creating and Editing Code

• Creating Code

• Editing Code

• Back to Editing Code...

• Naming Your Program File

Exploring Your First CircuitPython Program

• Imports & Libraries

• Setting Up The LED

• Loop-de-loops

• What Happens When My Code Finishes Running?

• What if I Don't Have the Loop?

Connecting to the Serial Console

• Are you using Mu?

• Serial Console Issues or Delays on Linux

26

28

33

36

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• Setting Permissions on Linux

• Using Something Else?

Interacting with the Serial Console

The REPL

• Entering the REPL

• Interacting with the REPL

• Returning to the Serial Console

CircuitPython Libraries

• The Adafruit Learn Guide Project Bundle

• The Adafruit CircuitPython Library Bundle

• Downloading the Adafruit CircuitPython Library Bundle

• The CircuitPython Community Library Bundle

• Downloading the CircuitPython Community Library Bundle

• Understanding the Bundle

• Example Files

• Copying Libraries to Your Board

• Understanding Which Libraries to Install

• Example: ImportError Due to Missing Library

• Library Install on Non-Express Boards

• Updating CircuitPython Libraries and Examples

• CircUp CLI Tool

CircuitPython Documentation

• CircuitPython Core Documentation

• CircuitPython Library Documentation

39

42

46

57

Recommended Editors

• Recommended editors

• Recommended only with particular settings or add-ons

• Editors that are NOT recommended

Advanced Serial Console on Windows

• Windows 7 and 8.1

• What's the COM?

• Install Putty

Advanced Serial Console on Mac

• What's the Port?

• Connect with screen

Advanced Serial Console on Linux

• What's the Port?

• Connect with screen

• Permissions on Linux

Frequently Asked Questions

• Using Older Versions

• Python Arithmetic

• Wireless Connectivity

• Asyncio and Interrupts

• Status RGB LED

• Memory Issues

64

65

69

71

75

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• Unsupported Hardware

Troubleshooting

• Always Run the Latest Version of CircuitPython and Libraries

• I have to continue using CircuitPython 7.x or earlier. Where can I find compatible libraries?

• Bootloader (boardnameBOOT) Drive Not Present

• Windows Explorer Locks Up When Accessing boardnameBOOT Drive

• Copying UF2 to boardnameBOOT Drive Hangs at 0% Copied

• CIRCUITPY Drive Does Not Appear or Disappears Quickly

• Device Errors or Problems on Windows

• Serial Console in Mu Not Displaying Anything

• code.py Restarts Constantly

• CircuitPython RGB Status Light

• CircuitPython 7.0.0 and Later

• CircuitPython 6.3.0 and earlier

• Serial console showing ValueError: Incompatible .mpy file

• CIRCUITPY Drive Issues

• Safe Mode

• To erase CIRCUITPY: storage.erase_filesystem()

• Erase CIRCUITPY Without Access to the REPL

• For the specific boards listed below:

• For SAMD21 non-Express boards that have a UF2 bootloader:

• For SAMD21 non-Express boards that do not have a UF2 bootloader:

• Running Out of File Space on SAMD21 Non-Express Boards

• Delete something!

• Use tabs

• On MacOS?

• Prevent & Remove MacOS Hidden Files

• Copy Files on MacOS Without Creating Hidden Files

• Other MacOS Space-Saving Tips

• Device Locked Up or Boot Looping

80

Welcome to the Community!

• Adafruit Discord

• CircuitPython.org

• Adafruit GitHub

• Adafruit Forums

• Read the Docs

Create Your settings.toml File

• CircuitPython settings.toml File

• settings.toml File Tips

• Accessing Your settings.toml Information in code.py

CircuitPython Internet Test

• The settings.toml File

Converting Arduino_GFX init strings to CircuitPython

• Using Arduino_GFX Init Codes

• Using Init Code Files

• Script Output

Determining Timings

• Using a Data Sheet

• Fill in the Settings

• Experimenting with Settings

98

107

110

115

119

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• Testing your Settings with CircuitPython

CircuitPython Display Setup

• Example TFT_PINS

• Example TFT_TIMINGS

• I/O Expander

• Display Initialization Code

• Sending Initialization Code via I2C IO Expander

• I2C Bus Speed

• Constructing the framebuffer and the display

• Dot clocks

CircuitPython Touch Display Usage

• Determining the I2C Address

• Initializing the Touch Controller

• Reading from the Touch Controller

• Example

Qualia S3 RGB-666 with TL021WVC02 2.1" 480x480 Round Display

• Initialization Codes

• Timings

• Example

Qualia S3 RGB-666 with TL034WVS05 3.4" 480x480 Square Display

• Initialization Codes

• Timings

• Example

123

135

139

142

Qualia S3 RGB-666 with TL040HDS20 4.0" 720x720 Square Display

• Initialization Codes

• Timings

• Example

Qualia S3 RGB-666 with TL032FWV01 3.2" 320x820 Bar Display

• Initialization Codes

• Timings

• Example

Arduino IDE Setup

Using with Arduino IDE

• Blink

• Select ESP32-S2/S3 Board in Arduino IDE

• Launch ESP32-S2/S3 ROM Bootloader

• Load Blink Sketch

WiFi Test

• WiFi Connection Test

• Secure Connection Example

• JSON Parsing Demo

146

149

153

156

160

Usage with Adafruit IO

• Install Libraries

• Adafruit IO Setup

• Code Usage

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171

Arduino Rainbow Demo

179

Arduino Touch Display Usage

• Determining the I2C Address

• Initializing the Touch Controller

• Reading from the Touch Controller

• Example

Install UF2 Bootloader

Factory Reset

• Factory Reset Firmware UF2

• Factory Reset and Bootloader Repair

• Download .bin and Enter Bootloader

• Step 1. Download the factory-reset-and-bootloader.bin file

• Step 2. Enter ROM bootloader mode

• The WebSerial ESPTool Method

• Connect

• Erase the Contents

• Program the ESP32-S2/S3

• The esptool Method (for advanced users)

• Install ESPTool.py

• Test the Installation

• Connect

• Erase the Flash

• Installing the Bootloader

• Reset the board

• Older Versions of Chrome

• TheFlash an Arduino Sketch Method

• Arduino IDE Setup

• Load the Blink Sketch

182

184

185

Downloads

• Schematic

• Fab Print

198

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Overview

There are things everyone loves: ice cream, kittens, and honkin' large TFT LCD

screens. We're no strangers to small TFT's -from our itsy 1.14" color display()that

graces many-a-TFT-Feather toour fancy 3.5" 320x480() breakout screen. But most

people who dabble or engineer with microcontrollers know that you sort of 'top out' at

320x480 - that's the largest resolution you can use with every day SPI or 8-bit 8080

interfaces. After that, you're in TTL-interfaceTFT land, where displays no longer have

an internal memory buffer and instead the controller has to continuously write

scanline data over a 16, 18 or 24 pin interface.

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RGB TTL interface TFT displays can get big: they start out at around4.3" diagonal

480x272, and can get to 800x480, 800x600 or even 720x720. For displays that big,

you need a lot of video RAM (800x480 at 24 bit color is just over 1MB), plenty of spare

GPIO to dedicate, and a peripheral that will DMA the video RAM out to the display

continuously. This is a setup familiar to people working with hefty microcontrollers or

microcomputers, the sort of device that run cell phones, or your car's GPS navigation

screen. But until now, nearly impossible to use on low cost microcontrollers.

The ESP32-S3 is the first low-cost microcontroller that has a built in peripheral that

can drive TTL displays, and it can come with enough PSRAM to buffer those large

images. For example, on theAdafruit Qualia ESP32-S3 for TTL RGB-666 Displays, we

use a S3 module with 16 MB of Flash and 8 MB of octal PSRAM. Using the built in RGB

display peripheral you can display graphics, images, animations or even video

(cinepak, natch!) with near-instantaneous updates since the whole screen gets

updated about 30 frames per second (FPS).

This dev board is designed to make it easy for you to explore displays that use the

'secondary standard' 40-pin RGB-666 connector. This pin order is most commonly

seen on square, round and bar displays.You'll want to compare the display you're

using to this datasheet(), and if it matches, you'll probably be good! One nice thing

about this connector ordering is that it also includes pins for capacitive touch overlay,

and we wire those up to the ESP32-S3's I2C port so you can also have touch control

with your display.

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Don't forget! This is just the development board, a display is not included.Use any

RGB-666 pinout display with or without a touch overlay. Note that you will need to

program in the driver initialization code, dimensions, and pulse widths in your

programming language. Here are some known-working displays that you can use in

Arduino and CircuitPython:

2.1" 480x480 Round with Capacitive Touch()

•

2.1" 480x480 Round without Touch()

•

4" 720x720 Square with Capacitive Touch()

•

4" 720x720 Round without Touch()

•

4.6" 960x320 Rectangular Bar()

•

On the Qualia board we have the S3 modules, with 16 pins connected to the TFT for

5-6-5 RGB color, plus HSync, VSync, Data Enable and Pixel Clock. There's a constant

current backlight control circuit using theTPS61169()which can get up to 30V

forward voltage and can be configured for 25mA-200mA in 25mA increments (default

is 25mA). Power and programming is provided over a USB C connector, wired to the

S3's native USB port. For debugging, the hardware UART TX pin is available as well.

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Since almost every GPIO is used, and almost allRGB-666 displays need to be

initialized over SPI, we put aPCA9554()I/O expander on the shared I2C bus. Arduino

or CircuitPython can be instructed on how to use the expander to reset and init the

display you have if necessary. The remaining expander pins are connected to two

right-angle buttons, and the display backlight.

The expander is what lets us have a full 4-pin SPI port and two more analog GPIO pins

-enough to wire up an MMC in 1-wire SDIO mode along with an I2S amplifier to make

an A/V playback demo(). Maybe we can even eat ice cream while watching kitten

vids!There is also the shared I2C port, we provide a Stemma QT / Qwiic port for easy

addition of any sensor or device you like.

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Pinouts

Microcontroller and WiFi

The main processor chip is

theEspressifESP32-S3with 3.3v logic/

power. It has 16MBof Flash and 8MBof

RAM.

The ESP32-S3 comes with WiFi and

Bluetooth LEbaked right in, though

CircuitPython only supports WiFi at this

time, not BLE on the S3 chip

40-Pin Display Connector

Not all 40-pin displays have the power pins in the same place. Hooking up a non

RGB666 display with the Qualia S3 risks damaging the display.

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IO Expander

There is a 40-pin display connector to

connect your display. Displays should be

connected with the pins of the cable down

towards the board and the colored side

facing you.

The Qualia S3 includes aPCA9554 IO

Expander. The IO Expander is connected

via the I2C bus. The main purpose of the

expander is to add additional pins to

communicate with the display.

Stemma QT Connector

The default address of the IO expander is

0x3F, but it can be changed by soldering

jumpers on the reverse side in case it

interferes with another I2C device.

There is a 4-pinStemma QTconnectoron

the left. The I2C has pullups to 3.3V power.

In CircuitPython, you can use the STEMMA

connector
with board.SCL and board.SDA ,
or board.STEMMA_I2C() .

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Reset and Boot0 Pins

Debug Pin

Resetis the Reset pin. Tie to ground to

manually reset the ESP32-S3.

TyingBoot0to ground while resetting will

place the ESP32-S3 in ROM bootloader

mode.

If you'd like to do lower level debugging,

we have the ESP32-S3's TXD0 debug pin

exposed as TX0 to view messages.

To read, you would connect a Serial UART

cable Receive connection here and the

cable ground connection to the GND pin.

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SPI Pins

The SPI pins of the ESP32-S3 are exposed

for communication with other SPI

hardware.

Each of these pins can alternatively be

used for digital I/O:

SCK is connected to board.TFT_SCK
Arduino 5 .
MISO is connected to board.TFT_MISO
Arduino 6 .
MOSI is connected to board.TFT_MOSI
Arduino 7 .
CS is connected to board.TFT_CS
Arduino 15 and includes a 10K Pull-up

resistor.

Analog Connector/Pins

On the bottom side towards the right,

there is a connector labeledA0. This is

a3-pin JST analog connectorfor sensors,

NeoPixels, or analog output or input.

For the JST connected, there is a jumper

above that can be cut and soldered to use

3V instead of 5V.

Along the bottom there are also pins
labeled A0 and A1 .

Each of these pins can be used for analog

inputs or digital I/O.

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Buttons

There are three buttons along the left side

of the Qualia S3.

The Reset buttonis located in the top

position. Click it once to re-start your

firmware. Click it again after about a half

second to enter bootloader mode.

The UPbutton is located in the middle and

is connected to the IO expander

The DN button, or Down button, is located

on the bottom and is connected to the IO

expander.

The expander implements a light pullup for

each of the buttons and pressing either of

them pulls the input low.

Backlight Jumpers

The Boot0 button is located between the

up button and the Microcontroller. Hold it

while pressing reset to enter ROM

Bootloader mode.

Soldering the bottom PWM jumper allows
using Pin A1 to control the backlight of

the display.

By default, 25mA is provided to the

backlight, but additional amperage can be

set by soldering the top jumpers to

provide up to 200mA if needed.

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IO Expander Address Jumpers

Parallel Interface Jumpers

On the reverse, are a couple of solderable

jumpers to change the I2C address of the

IO Expander. By default, both jumpers are

set to high, providing a default address of

0x3F. However, it can be set between

0x3B-0x3F.



The IM0 and IM1 jumpers are for selecting

the mode of the parallel interface for the

display. The default selection should work

for most displays.

CircuitPython

CircuitPython() is a derivative of MicroPython() designed to simplify experimentation

and education on low-cost microcontrollers. It makes it easier than ever to get

prototyping by requiring no upfront desktop software downloads. Simply copy and

edit files on the CIRCUITPY drive to iterate.

CircuitPython Quickstart

Follow this step-by-step to quickly get CircuitPython running on your board.

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This microcontroller requires the latest unstable (development)release of

CircuitPython. Click below to visit the downloads page on circuitpython.org for your

board. Then, Browse S3 under Absolute Newest.

Download the latest version of

CircuitPython for this board via

circuitpython.org

Click the link above to download the latest

CircuitPython UF2 file.

Save it wherever is convenient for you.

The Qualia S3 does not have a RGB status LED

Plug your board into your computer, using a known-good data-sync cable, directly, or

via an adapter if needed.

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Double-click the reset button (highlighted in red above), and you will see the RGB

status LED(s) turn green (highlighted in green above). If you see red, try another port,

or if you're using an adapter or hub, try without the hub, or different adapter or hub.

This board does not have a Neopixel, so you will need to just double tap the

reset button.

For this board, tap reset and wait about a half a second and then tap reset again.

Some boards may not have a UF2 bootloader installed. If double-clicking does

not work, follow the instructions on the "Install UF2 Bootloader" page in this

guide.

If double-clicking doesn't work the first time, try again. Sometimes it can take a few

tries to get the rhythm right!

A lot of people end up using charge-only USB cables and it is very frustrating! Make

sure you have a USB cable you know is good for data sync.

You will see a new disk drive appear called

TFT_S3BOOT.



Drag the adafruit_circuitpython_etc.uf2 file

to TFT_S3BOOT.

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The BOOT drive will disappear and a new

disk drive called CIRCUITPY will appear.

That's it!

The CIRCUITPY Drive

When CircuitPython finishes installing, or you plug a CircuitPython board into your

computer with CircuitPython already installed, the board shows up on your computer

as a USB drive called CIRCUITPY.

The CIRCUITPY drive is where your code and the necessary libraries and files will live.

You can edit your code directly on this drive and when you save, it will run

automatically. When you create and edit code, you'll save your code in a code.py file

located on the CIRCUITPY drive.If you're following along with a Learn guide, you can

paste the contents of the tutorial example into code.py on the CIRCUITPY drive and

save it to run the example.

With a fresh CircuitPython install, on your CIRCUITPY drive, you'll find a code.py file
containing print("Hello World!") and an empty lib folder. If your CIRCUITPY

drive does not contain a code.py file, you can easily create one and save it to the

drive. CircuitPython looks for code.py and executes the code within the file

automatically when the board starts up or resets. Following a change to the contents

of CIRCUITPY, such as making a change to the code.py file, the board will reset, and

the code will be run. You do not need to manually run the code. This is what makes it

so easy to get started with your project and update your code!

Note that all changes to the contents of CIRCUITPY, such as saving a new file,

renaming a current file, or deleting an existing file will trigger a reset of the board.

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Boards Without CIRCUITPY

CircuitPython is available for some microcontrollers that do not support native USB.

Those boards cannot present a CIRCUITPY drive. This includes boards using ESP32

or ESP32-C3 microcontrollers.

On these boards, there are alternative ways to transfer and edit files. You can use the

Thonny editor(), which uses hidden commands sent to the REPL to read and write

files. Or you can use the CircuitPython web workflow, introduced in Circuitpython 8.

The web workflow provides browser-based WiFi access to the CircuitPython

filesystem. These guides will help you with the web workflow:

CircuitPython on ESP32 Quick Start()

•

CircuitPython Web Workflow Code Editor Quick Start()

•

CircuitPython Pins and Modules

CircuitPython is designed to run on microcontrollers and allows you to interface with

all kinds of sensors, inputs and other hardware peripherals. There are tons of guides

showing how to wire up a circuit, and use CircuitPython to, for example, read data

from a sensor, or detect a button press. Most CircuitPython code includes hardware
setup which requires various modules, such as board or digitalio . You import

these modules and then use them in your code. How does CircuitPython know to look

for hardware in the specific place you connected it, and where do these modules

come from?

This page explains both. You'll learn how CircuitPython finds the pins on your

microcontroller board, including how to find the available pins for your board and

what each pin is named. You'll also learn about the modules built into CircuitPython,

including how to find all the modules available for your board.

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CircuitPython Pins

When using hardware peripherals with a CircuitPython compatible microcontroller,

you'll almost certainly be utilising pins. This section will cover how to access your

board's pins using CircuitPython, how to discover what pins and board-specific

objects are available in CircuitPython for your board, how to use the board-specific

objects, and how to determine all available pin names for a given pin on your board.

import board

When you're using any kind of hardware peripherals wired up to your microcontroller
board, the import list in your code will include import board . The board module is

built into CircuitPython, and is used to provide access to a series of board-specific

objects, including pins. Take a look at your microcontroller board. You'll notice that

next to the pins are pin labels. You can always access a pin by its pin label. However,

there are almost always multiple names for a given pin.

To see all the available board-specific objects and pins for your board, enter the REPL
( >>> ) and run the following commands:

import board
dir(board)

Here is the output for the QT Py SAMD21. You may have a different board, and this list

will vary, based on the board.

The following pins have labels on the physical QT Py SAMD21 board: A0, A1, A2, A3,

SDA, SCL, TX, RX, SCK, MISO, and MOSI. You see that there are many more entries
available in board than the labels on the QT Py.

You can use the pin names on the physical board, regardless of whether they seem to

be specific to a certain protocol.

For example, you do not have to use the SDA pin for I2C - you can use it for a button

or LED.

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On the flip side, there may be multiple names for one pin. For example, on the QT Py

SAMD21, pin A0 is labeled on the physical board silkscreen, but it is available in
CircuitPython as both A0 and D0 . For more information on finding all the names for a

given pin, see the What Are All the Available Pin Names?() section below.

The results of dir(board) for CircuitPython compatible boards will look similar to

the results for the QT Py SAMD21 in terms of the pin names, e.g. A0, D0, etc.

However, some boards, for example, the Metro ESP32-S2, have different styled pin

names. Here is the output for the Metro ESP32-S2.

Note that most of the pins are named in an IO# style, such as IO1 and IO2. Those pins

on the physical board are labeled only with a number, so an easy way to know how to

access them in CircuitPython, is to run those commands in the REPL and find the pin

naming scheme.

If your code is failing to run because it can't find a pin name you provided, verify

that you have the proper pin name by running these commands in the REPL.

I2C, SPI, and UART

You'll also see there are often (but not always!) three special board-specific objects
included: I2C , SPI , and UART - each one is for the default pin-set used for each of

the three common protocol busses they are named for. These are called singletons.

What's a singleton? When you create an object in CircuitPython, you are instantiating

('creating') it. Instantiating an object means you are creating an instance of the object

with the unique values that are provided, or "passed", to it.

For example, When you instantiate an I2C object using the busio module, it expects

two pins: clock and data, typically SCL and SDA. It often looks like this:

i2c = busio.I2C(board.SCL, board.SDA)

Then, you pass the I2C object to a driver for the hardware you're using. For example,

if you were using the TSL2591 light sensor and its CircuitPython library, the next line

of code would be:

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tsl2591 = adafruit_tsl2591.TSL2591(i2c)

However, CircuitPython makes this simpler by including the I2C singleton in the boa

rd module. Instead of the two lines of code above, you simply provide the singleton

as the I2C object. So if you were using the TSL2591 and its CircuitPython library, the

two above lines of code would be replaced with:

tsl2591 = adafruit_tsl2591.TSL2591(board.I2C())

The board.I2C(), board.SPI(), and board.UART() singletons do not exist on all

boards. They exist if there are board markings for the default pins for those

devices.

This eliminates the need for the busio module, and simplifies the code. Behind the
scenes, the board.I2C()  object is instantiated when you call it, but not before, and

on subsequent calls, it returns the same object. Basically, it does not create an object

until you need it, and provides the same object every time you need it. You can call

board.I2C() as many times as you like, and it will always return the same object.

The UART/SPI/I2C singletons will use the 'default' bus pins for each board - often

labeled as RX/TX (UART), MOSI/MISO/SCK (SPI), or SDA/SCL (I2C). Check your

board documentation/pinout for the default busses.

What Are All the Available Names?

Many pins on CircuitPython compatible microcontroller boards have multiple names,

however, typically, there's only one name labeled on the physical board. So how do

you find out what the other available pin names are? Simple, with the following script!

Each line printed out to the serial console contains the set of names for a particular

pin.

On a microcontroller board running CircuitPython, first, connect to the serial console.

In the example below, click the Download Project Bundle button below to download

the necessary libraries and the code.py file in a zip file. Extract the contents of the zip

file, open the directory CircuitPython_Essentials/Pin_Map_Script/ and then click on

the directory that matches the version of CircuitPython you're using and copy the

contents of that directory to your CIRCUITPY drive.

Your CIRCUITPY drive should now look similar to the following image:

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# SPDX-FileCopyrightText: 2020 anecdata for Adafruit Industries
# SPDX-FileCopyrightText: 2021 Neradoc for Adafruit Industries
# SPDX-FileCopyrightText: 2021-2023 Kattni Rembor for Adafruit Industries
# SPDX-FileCopyrightText: 2023 Dan Halbert for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""CircuitPython Essentials Pin Map Script"""
import microcontroller
import board
try:
import cyw43 # raspberrypi
except ImportError:
cyw43 = None

board_pins = []
for pin in dir(microcontroller.pin):
if (isinstance(getattr(microcontroller.pin, pin), microcontroller.Pin) or
(cyw43 and isinstance(getattr(microcontroller.pin, pin), cyw43.CywPin))):
pins = []
for alias in dir(board):
if getattr(board, alias) is getattr(microcontroller.pin, pin):
pins.append(f"board.{alias}")
# Add the original GPIO name, in parentheses.
if pins:
# Only include pins that are in board.
pins.append(f"({str(pin)})")
board_pins.append(" ".join(pins))

for pins in sorted(board_pins):
print(pins)

Here is the result when this script is run on QT Py SAMD21:

Each line represents a single pin. Find the line containing the pin name that's labeled

on the physical board, and you'll find the other names available for that pin. For
example, the first pin on the board is labeled A0. The first line in the output is board.

A0 board.D0 (PA02) . This means that you can access pin A0 in CircuitPython using

both board.A0 and board.D0 .

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The pins in parentheses are the microcontroller pin names. See the next section for

more info on those.

You'll notice there are two "pins" that aren't labeled on the board but appear in the
list: board.NEOPIXEL and board.NEOPIXEL_POWER . Many boards have several of

these special pins that give you access to built-in board hardware, such as an LED or

an on-board sensor. The QT Py SAMD21 only has one on-board extra piece of

hardware, a NeoPixel LED, so there's only the one available in the list. But you can

also control whether or not power is applied to the NeoPixel, so there's a separate pin

for that.

That's all there is to figuring out the available names for a pin on a compatible

microcontroller board in CircuitPython!

Microcontroller Pin Names

The pin names available to you in the CircuitPython board module are not the same

as the names of the pins on the microcontroller itself. The board pin names are

aliases to the microcontroller pin names. If you look at the datasheet for your

microcontroller, you'll likely find a pinout with a series of pin names, such as "PA18" or

"GPIO5". If you want to get to the actual microcontroller pin name in CircuitPython,
you'll need the microcontroller.pin module. As with board , you can run dir(mi

crocontroller.pin) in the REPL to receive a list of the microcontroller pin names.

CircuitPython Built-In Modules

There is a set of modules used in most CircuitPython programs. One or more of these

modules is always used in projects involving hardware. Often hardware requires

installing a separate library from the Adafruit CircuitPython Bundle. But, if you try to
find board or digitalio in the same bundle, you'll come up lacking. So, where do

these modules come from? They're built into CircuitPython! You can find an

comprehensive list of built-in CircuitPython modules and the technical details of their

functionality from CircuitPython here() and the Python-like modules included here().

However, not every module is available for every board due to size constraints or

hardware limitations. How do you find out what modules are available for your board?

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There are two options for this. You can check the support matrix(), and search for

your board by name. Or, you can use the REPL.

Plug in your board, connect to the serial console and enter the REPL. Type the

following command.

help("modules")

That's it! You now know two ways to find all of the modules built into CircuitPython for

your compatible microcontroller board.

Installing the Mu Editor

Mu is a simple code editor that works with the Adafruit CircuitPython boards. It's

written in Python and works on Windows, MacOS, Linux and Raspberry Pi. The serial

console is built right in so you get immediate feedback from your board's serial

output!

Mu is our recommended editor - please use it (unless you are an experienced

coder with a favorite editor already!).

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Download and Install Mu

Download Mu fromhttps://codewith.mu().

Click theDownload link for downloads and

installation instructions.

Click Start Hereto find a wealth of other

information, including extensive tutorials

and and how-to's.



Windows users: due to the nature of MSI installers, please remove old versions of

Mu before installing the latest version.

Starting Up Mu

The first time you start Mu, you will be

prompted to select your 'mode' - you can

always change your mind later. For now

please select CircuitPython!

The current mode is displayed in the lower

right corner of the window, next to the

"gear" icon. If the mode says "Microbit" or

something else, click the Mode button in

the upper left, and then choose

"CircuitPython" in the dialog box that

appears.

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Mu attempts to auto-detect your board on

startup, so if you do not have a

CircuitPython board plugged in with a

CIRCUITPY drive available, Mu will inform

you where it will store any code you save

until you plug in a board.

To avoid this warning, plug in a board and

ensure that the CIRCUITPY drive is

mounted before starting Mu.

Using Mu

You can now explore Mu! The three main sections of the window are labeled below;

the button bar, the text editor, and the serial console / REPL.

Now you're ready to code! Let's keep going...

Creating and Editing Code

One of the best things about CircuitPython is how simple it is to get code up and

running. This section covers how to create and edit your first CircuitPython program.

To create and edit code, all you'll need is an editor. There are many options. Adafruit

strongly recommends using Mu! It's designed for CircuitPython, and it's really simple

and easy to use, with a built in serial console!

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If you don't or can't use Mu, there are a number of other editors that work quite well.

The Recommended Editors page() has more details. Otherwise, make sure you do

"Eject" or "Safe Remove" on Windows or "sync" on Linux after writing a file if you

aren't using Mu. (This is not a problem on MacOS.)

Creating Code

Installing CircuitPython generates a

code.py file on your CIRCUITPY drive. To

begin your own program, open your editor,

and load the code.py file from the

CIRCUITPY drive.

If you are using Mu, click the Load button

in the button bar, navigate to the

CIRCUITPY drive, and choose code.py.

Copy and paste the following code into your editor:

import board
import digitalio
import time

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
led.value = True
time.sleep(0.5)
led.value = False
time.sleep(0.5)

The KB2040, QT Py and the Trinkeys do not have a built-in little red LED! There is

an addressable RGB NeoPixel LED. The above example will NOT work on the

KB2040, QT Py or the Trinkeys!

If you're using a KB2040, QT Py or a Trinkey, please download the NeoPixel blink

example().

The NeoPixel blink example uses the onboard NeoPixel, but the time code is the

same. You can use the linked NeoPixel Blink example to follow along with this

guide page.

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It will look like this. Note that under the

while True: line, the next four lines

begin with four spaces to indent them, and

they're indented exactly the same amount.

All the lines before that have no spaces

before the text.

Save the code.py file on your CIRCUITPY

drive.

The little LED should now be blinking. Once per half-second.

Congratulations, you've just run your first CircuitPython program!

On most boards you'll find a tiny red LED.

On the ItsyBitsy nRF52840, you'll find a tiny blue LED.

On QT Py M0, QT Py RP2040, and the Trinkey series, you will find only an RGB

NeoPixel LED.

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Editing Code

To edit code, open thecode.pyfile on your

CIRCUITPY drive into your editor.



Make the desired changes to your code.

Save the file. That's it!

Your code changes are run as soon as the file is done saving.

There's one warning before you continue...

Don't click reset or unplug your board!

The CircuitPython code on your board detects when the files are changed or written

and will automatically re-start your code. This makes coding very fast because you

save, and it re-runs. If you unplug or reset the board before your computer finishes

writing the file to your board, you can corrupt the drive. If this happens, you may lose

the code you've written, so it's important to backup your code to your computer

regularly.

There are a couple of ways to avoid filesystem corruption.

1. Use an editor that writes out the file completely when you save it.

Check out the Recommended Editors page() for details on different editing options.

If you are dragging a file from your host computer onto the CIRCUITPY drive, you

still need to do step 2. Eject or Sync (below) to make sure the file is completely

written.

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2. Eject or Sync the Drive After Writing

If you are using one of our not-recommended-editors, not all is lost! You can still make

it work.

On Windows, you can Eject or Safe Remove the CIRCUITPY drive. It won't actually

eject, but it will force the operating system to save your file to disk. On Linux, use the

sync command in a terminal to force the write to disk.

You also need to do this if you use Windows Explorer or a Linux graphical file

manager to drag a file onto CIRCUITPY.

Oh No I Did Something Wrong and Now The CIRCUITPY Drive Doesn't Show Up!!!

Don't worry! Corrupting the drive isn't the end of the world (or your board!). If this

happens, follow the steps found on the Troubleshooting() page of every board

guide to get your board up and running again.

Back to Editing Code...

Now! Let's try editing the program you added to your board. Open your code.py file
into your editor. You'll make a simple change. Change the first 0.5 to 0.1 . The code

should look like this:

import board
import digitalio
import time

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
led.value = True
time.sleep(0.1)
led.value = False
time.sleep(0.5)

Leave the rest of the code as-is. Save your file. See what happens to the LED on your

board? Something changed! Do you know why?

You don't have to stop there! Let's keep going. Change the second 0.5 to 0.1 so it

looks like this:

while True:
led.value = True

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time.sleep(0.1)
led.value = False
time.sleep(0.1)

Now it blinks really fast! You decreased the both time that the code leaves the LED on

and off!

Now try increasing both of the 0.1 to 1 . Your LED will blink much more slowly

because you've increased the amount of time that the LED is turned on and off.

Well done! You're doing great! You're ready to start into new examples and edit them

to see what happens! These were simple changes, but major changes are done using

the same process. Make your desired change, save it, and get the results. That's

really all there is to it!

Naming Your Program File

CircuitPython looks for a code file on the board to run. There are four options: code.tx

t, code.py, main.txt and main.py. CircuitPython looks for those files, in that order, and

then runs the first one it finds. While code.py is the recommended name for your code

file, it is important to know that the other options exist. If your program doesn't seem

to be updating as you work, make sure you haven't created another code file that's

being read instead of the one you're working on.

Exploring Your First CircuitPython Program

First, you'll take a look at the code you're editing.

Here is the original code again:

import board
import digitalio
import time

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
led.value = True
time.sleep(0.5)
led.value = False
time.sleep(0.5)

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Imports & Libraries

Each CircuitPython program you run needs to have a lot of information to work. The

reason CircuitPython is so simple to use is that most of that information is stored in

other files and works in the background. The files built into CircuitPython are called m

odules, and the files you load separately are called libraries. Modules are built into

CircuitPython. Libraries are stored on your CIRCUITPY drive in a folder called lib.

import board
import digitalio
import time

The import statements tells the board that you're going to use a particular library or
module in your code. In this example, you imported three modules: board ,

digitalio , and time . All three of these modules are built into CircuitPython, so no

separate library files are needed. That's one of the things that makes this an excellent

first example. You don't need anything extra to make it work!

These three modules each have a purpose. The first one, board , gives you access to
the hardware on your board. The second, digitalio , lets you access that hardware
as inputs/outputs.The third, time , let's you control the flow of your code in multiple

ways, including passing time by 'sleeping'.

Setting Up The LED

The next two lines setup the code to use the LED.

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

Your board knows the red LED as LED . So, you initialise that pin, and you set it to
output. You set led to equal the rest of that information so you don't have to type it

all out again later in our code.

Loop-de-loops

The third section starts with a while statement. while True: essentially means,
"forever do the following:". while True: creates a loop. Code will loop "while" the
condition is "true" (vs. false), and as True is never False, the code will loop forever.
All code that is indented under while True: is "inside" the loop.

Inside our loop, you have four items:

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while True:
led.value = True
time.sleep(0.5)
led.value = False
time.sleep(0.5)

First, you have led.value = True . This line tells the LED to turn on. On the next
line, you have time.sleep(0.5) . This line is telling CircuitPython to pause running

code for 0.5 seconds. Since this is between turning the led on and off, the led will be

on for 0.5 seconds.

The next two lines are similar. led.value = False tells the LED to turn off, and tim

e.sleep(0.5) tells CircuitPython to pause for another 0.5 seconds. This occurs

between turning the led off and back on so the LED will be off for 0.5 seconds too.

Then the loop will begin again, and continue to do so as long as the code is running!

So, when you changed the first 0.5 to 0.1 , you decreased the amount of time that

the code leaves the LED on. So it blinks on really quickly before turning off!

Great job! You've edited code in a CircuitPython program!

What Happens When My Code Finishes Running?

When your code finishes running, CircuitPython resets your microcontroller board to

prepare it for the next run of code. That means any set up you did earlier no longer

applies, and the pin states are reset.

For example, try reducing the code snippet above by eliminating the loop entirely,
and replacing it with led.value = True . The LED will flash almost too quickly to

see, and turn off. This is because the code finishes running and resets the pin state,

and the LED is no longer receiving a signal.

To that end, most CircuitPython programs involve some kind of loop, infinite or

otherwise.

What if I Don't Have the Loop?

If you don't have the loop, the code will run to the end and exit. This can lead to some

unexpected behavior in simple programs like this since the "exit" also resets the state

of the hardware. This is a different behavior than running commands via REPL. So if

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you are writing a simple program that doesn't seem to work, you may need to add a

loop to the end so the program doesn't exit.

The simplest loop would be:

while True:
pass

And remember - you can press CTRL+C to exit the loop.

See also the Behavior section in the docs().

Connecting to the Serial Console

One of the staples of CircuitPython (and programming in general!) is something called

a "print statement". This is a line you include in your code that causes your code to

output text. A print statement in CircuitPython (and Python) looks like this:

print("Hello, world!")

This line in your code.py would result in:

Hello, world!

However, these print statements need somewhere to display. That's where the serial

console comes in!

The serial console receives output from your CircuitPython board sent over USB and

displays it so you can see it. This is necessary when you've included a print statement

in your code and you'd like to see what you printed. It is also helpful for

troubleshooting errors, because your board will send errors and the serial console will

display those too.

The serial console requires an editor that has a built in terminal, or a separate

terminal program. A terminal is a program that gives you a text-based interface to

perform various tasks.

Are you using Mu?

If so, good news! The serial consoleis built into Mu and willautodetect your board

making using the serial console really really easy.

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First, make sure your CircuitPython board

is plugged in.

If you open Mu without a board plugged

in, you may encounter the error seen here,

letting you know no CircuitPython board

was found and indicating where your code

will be stored until you plug in a board.

If you are using Windows 7, make sure you

installed the drivers().

Once you've opened Mu with your board plugged in, look for the Serial button in the

button bar and click it.

The Mu window will split in two, horizontally, and display the serial console at the

bottom.

If nothing appears in the serial console, it may mean your code is done running

or has no print statements in it. Click into the serial console part of Mu, and press

CTRL+D to reload.

Serial Console Issues or Delays on Linux

If you're on Linux, and are seeing multi-second delays connecting to the serial

console, or are seeing "AT" and other gibberish when you connect, then the

modemmanager service might be interfering. Just remove it; it doesn't have much use

unless you're still using dial-up modems.

To remove modemmanager , type the following command at a shell:

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sudo apt purge modemmanager

Setting Permissions on Linux

On Linux, if you see an error box something like the one below when you press the S

erial button, you need to add yourself to a user group to have permission to connect

to the serial console.

On Ubuntu and Debian, add yourself to the dialout group by doing:

sudo adduser $USER dialout

After running the command above, reboot your machine to gain access to the group.

On other Linux distributions, the group you need may be different. See the Advanced

Serial Console on Linux()for details on how to add yourself to the right group.

Using Something Else?

If you're not using Mu to edit, are using or if for some reason you are not a fan of its

built in serial console, you can run the serial console from a separate program.

Windows requires you to download a terminal program. Check out the Advanced

Serial Console on Windows page for more details.()

MacOS has Terminal built in, though there are other options available for download. C

heck the Advanced Serial Console on Mac page for more details.()

Linux has a terminal program built in, though other options are available for

download. Check the Advanced Serial Console on Linux page for more details.()

Once connected, you'll see something like the following.

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Interacting with the Serial Console

Once you've successfully connected to the serial console, it's time to start using it.

The code you wrote earlier has no output to the serial console. So, you're going to

edit it to create some output.

Open your code.py file into your editor, and include a print statement. You can print

anything you like! Just include your phrase between the quotation marks inside the

parentheses. For example:

import board
import digitalio
import time

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
print("Hello, CircuitPython!")
led.value = True
time.sleep(1)
led.value = False
time.sleep(1)

Save your file.

Now, let's go take a look at the window with our connection to the serial console.

Excellent! Our print statement is showing up in our console! Try changing the printed

text to something else.

import board
import digitalio
import time

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led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
print("Hello back to you!")
led.value = True
time.sleep(1)
led.value = False
time.sleep(1)

Keep your serial console window where you can see it. Save your file. You'll see what

the serial console displays when the board reboots. Then you'll see your new change!

The Traceback (most recent call last): is telling you the last thing your board

was doing before you saved your file. This is normal behavior and will happen every

time the board resets. This is really handy for troubleshooting. Let's introduce an error

so you can see how it is used.

Delete the e at the end of True from the line led.value = True so that it says le

d.value = Tru

import board
import digitalio
import time

led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

while True:
print("Hello back to you!")
led.value = Tru
time.sleep(1)
led.value = False
time.sleep(1)

Save your file. You will notice that your red LED will stop blinking, and you may have a

colored status LED blinking at you. This is because the code is no longer correct and

can no longer run properly. You need to fix it!

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Usually when you run into errors, it's not because you introduced them on purpose.

You may have 200 lines of code, and have no idea where your error could be hiding.

This is where the serial console can help. Let's take a look!

The Traceback (most recent call last): is telling you that the last thing it was
able to run was line 10 in your code. The next line is your error: NameError: name

'Tru' is not defined . This error might not mean a lot to you, but combined with

knowing the issue is on line 10, it gives you a great place to start!

Go back to your code, and take a look at line 10. Obviously, you know what the

problem is already. But if you didn't, you'd want to look at line 10 and see if you could

figure it out. If you're still unsure, try googling the error to get some help. In this case,

you know what to look for. You spelled True wrong. Fix the typo and save your file.

Nice job fixing the error! Your serial console is streaming and your red LED Is blinking

again.

The serial console will display any output generated by your code. Some sensors,

such as a humidity sensor or a thermistor, receive data and you can use print

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statements to display that information. You can also use print statements for

troubleshooting, which is called "print debugging". Essentially, if your code isn't

working, and you want to know where it's failing, you can put print statements in

various places to see where it stops printing.

The serial console has many uses, and is an amazing tool overall for learning and

programming!

The REPL

The other feature of the serial connection is the Read-Evaluate-Print-Loop, or REPL.

The REPL allows you to enter individual lines of code and have them run immediately.

It's really handy if you're running into trouble with a particular program and can't

figure out why. It's interactive so it's great for testing new ideas.

Entering the REPL

To use the REPL, you first need to be connected to the serial console. Once that

connection has been established, you'll want to press CTRL+C.

If there is code running, in this case code measuring distance, it will stop and you'll
see Press any key to enter the REPL. Use CTRL-D to reload. Follow those

instructions, and press any key on your keyboard.

The Traceback (most recent call last): is telling you the last thing your board
was doing before you pressed Ctrl + C and interrupted it. The KeyboardInterrupt

is you pressing CTRL+C. This information can be handy when troubleshooting, but for

now, don't worry about it. Just note that it is expected behavior.

If your code.py file is empty or does not contain a loop, it will show an empty output
and Code done running. . There is no information about what your board was

doing before you interrupted it because there is no code running.

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If you have no code.py on your CIRCUITPY drive, you will enter the REPL immediately

after pressing CTRL+C. Again, there is no information about what your board was

doing before you interrupted it because there is no code running.

Regardless, once you press a key you'll see a >>> prompt welcoming you to the

REPL!

If you have trouble getting to the >>> prompt, try pressing Ctrl + C a few more times.

The first thing you get from the REPL is information about your board.

This line tells you the version of CircuitPython you're using and when it was released.

Next, it gives you the type of board you're using and the type of microcontroller the

board uses. Each part of this may be different for your board depending on the

versions you're working with.

This is followed by the CircuitPython prompt.

Interacting with the REPL

From this prompt you can run all sorts of commands and code. The first thing you'll do
is run help() . This will tell you where to start exploring the REPL. To run code in the

REPL, type it in next to the REPL prompt.

Type help() next to the prompt in the REPL.

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Then press enter. You should then see a message.

First part of the message is another reference to the version of CircuitPython you're

using. Second, a URL for the CircuitPython related project guides. Then... wait. What's
this? To list built-in modules type `help("modules")`. Remember the

modules you learned about while going through creating code? That's exactly what

this is talking about! This is a perfect place to start. Let's take a look!

Type help("modules") into the REPL next to the prompt, and press enter.

This is a list of all the core modules built into CircuitPython, including board .
Remember, board contains all of the pins on the board that you can use in your

code. From the REPL, you are able to see that list!

Type import board into the REPL and press enter. It'll go to a new prompt. It might
look like nothing happened, but that's not the case! If you recall, the import

statement simply tells the code to expect to do something with that module. In this

case, it's telling the REPL that you plan to do something with that module.

Next, type dir(board) into the REPL and press enter.

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This is a list of all of the pins on your board that are available for you to use in your

code. Each board's list will differ slightly depending on the number of pins available.
Do you see LED ? That's the pin you used to blink the red LED!

The REPL can also be used to run code. Be aware that any code you enter into the

REPL isn't saved anywhere. If you're testing something new that you'd like to keep,

make sure you have it saved somewhere on your computer as well!

Every programmer in every programming language starts with a piece of code that

says, "Hello, World." You're going to say hello to something else. Type into the REPL:

print("Hello, CircuitPython!")

Then press enter.

That's all there is to running code in the REPL! Nice job!

You can write single lines of code that run stand-alone. You can also write entire

programs into the REPL to test them. Remember that nothing typed into the REPL is

saved.

There's a lot the REPL can do for you. It's great for testing new ideas if you want to

see if a few new lines of code will work. It's fantastic for troubleshooting code by

entering it one line at a time and finding out where it fails. It lets you see what

modules are available and explore those modules.

Try typing more into the REPL to see what happens!

Everything typed into the REPL is ephemeral. Once you reload the REPL or return

to the serial console, nothing you typed will be retained in any memory space. So

be sure to save any desired code you wrote somewhere else, or you'll lose it

when you leave the current REPL instance!

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Returning to the Serial Console

When you're ready to leave the REPL and return to the serial console, simply press CT

RL+D. This will reload your board and reenter the serial console. You will restart the

program you had running before entering the REPL. In the console window, you'll see

any output from the program you had running. And if your program was affecting

anything visual on the board, you'll see that start up again as well.

You can return to the REPL at any time!

CircuitPython Libraries

As CircuitPython development continues and there are new releases, Adafruit

will stop supporting older releases. Visit https://circuitpython.org/downloads to

download the latest version of CircuitPython for your board. You must download

the CircuitPython Library Bundle that matches your version of CircuitPython.

Please update CircuitPython and then visit https://circuitpython.org/libraries to

download the latest Library Bundle.

Each CircuitPython program you run needs to have a lot of information to work. The

reason CircuitPython is so simple to use is that most of that information is stored in

other files and works in the background. These files are called libraries. Some of them

are built into CircuitPython. Others are stored on your CIRCUITPY drive in a folder

called lib. Part of what makes CircuitPython so great is its ability to store code

separately from the firmware itself. Storing code separately from the firmware makes

it easier to update both the code you write and the libraries you depend.

Your board may ship with a lib folder already, it's in the base directory of the drive. If

not, simply create the folder yourself. When you first install CircuitPython, an empty lib

directory will be created for you.

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CircuitPython libraries work in the same way as regular Python modules so the Python

docs() are an excellent reference for how it all should work. In Python terms, you can

place our library files in the lib directory because it's part of the Python path by

default.

One downside of this approach of separate libraries is that they are not built in. To

use them, one needs to copy them to the CIRCUITPY drive before they can be used.

Fortunately, there is a library bundle.

The bundle and the library releases on GitHub also feature optimized versions of the

libraries with the .mpy file extension. These files take less space on the drive and

have a smaller memory footprint as they are loaded.

Due to the regular updates and space constraints, Adafruit does not ship boards with

the entire bundle. Therefore, you will need to load the libraries you need when you

begin working with your board. You can find example code in the guides for your

board that depends on external libraries.

Either way, as you start to explore CircuitPython, you'll want to know how to get

libraries on board.

The Adafruit Learn Guide Project Bundle

The quickest and easiest way to get going with a project from the Adafruit Learn

System is by utilising the Project Bundle. Most guides now have a Download Project

Bundle button available at the top of the full code example embed. This button

downloads all the necessary files, including images, etc., to get the guide project up

and running. Simply click, open the resulting zip, copy over the right files, and you're

good to go!

The first step is to find the Download Project Bundle button in the guide you're

working on.

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The Download Project Bundle button is only available on full demo code

embedded from GitHub in a Learn guide. Code snippets will NOT have the

button available.

When you copy the contents of the Project Bundle to your CIRCUITPY drive, it

will replace all the existing content! If you don't want to lose anything, ensure you

copy your current code to your computer before you copy over the new Project

Bundle content!

The Download Project Bundle button downloads a zip file. This zip contains a series

of directories, nested within which is the code.py, any applicable assets like images or

audio, and the lib/ folder containing all the necessary libraries. The following zip was

downloaded from the Piano in the Key of Lime guide.

The Piano in the Key of Lime guide was chosen as an example. That guide is

specific to Circuit Playground Express, and cannot be used on all boards. Do not

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expect to download that exact bundle and have it work on your non-CPX

microcontroller.

When you open the zip, you'll find some nested directories. Navigate through them

until you find what you need. You'll eventually find a directory for your CircuitPython

version (in this case, 7.x). In the version directory, you'll find the file and directory you

need: code.py and lib/. Once you find the content you need, you can copy it all over

to your CIRCUITPY drive, replacing any files already on the drive with the files from

the freshly downloaded zip.

In some cases, there will be other files such as audio or images in the same

directory as code.py and lib/. Make sure you include all the files when you copy

things over!

Once you copy over all the relevant files, the project should begin running! If you find

that the project is not running as expected, make sure you've copied ALL of the

project files onto your microcontroller board.

That's all there is to using the Project Bundle!

The Adafruit CircuitPython Library Bundle

Adafruit provides CircuitPython libraries for much of the hardware they provide,

including sensors, breakouts and more. To eliminate the need for searching for each

library individually, the libraries are available together in the Adafruit CircuitPython

Library Bundle. The bundle contains all the files needed to use each library.

Downloading the Adafruit CircuitPython Library Bundle

You can download the latest Adafruit CircuitPython Library Bundle release by clicking

the button below. The libraries are being constantly updated and improved, so you'll

always want to download the latest bundle.

Match up the bundle version with the version of CircuitPython you are running. For

example, you would download the 6.x library bundle if you're running any version of

CircuitPython 6, or the 7.x library bundle if you're running any version of CircuitPython

7, etc. If you mix libraries with major CircuitPython versions, you will get incompatible

mpy errors due to changes in library interfaces possible during major version

changes.

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Click to visit circuitpython.org for the

latest Adafruit CircuitPython Library

Bundle

Download the bundle version that matches your CircuitPython firmware version. If you

don't know the version, check the version info in boot_out.txt file on the CIRCUITPY

drive, or the initial prompt in the CircuitPython REPL. For example, if you're running

v7.0.0, download the 7.x library bundle.

There's also a py bundle which contains the uncompressed python files, you probably

don't want that unless you are doing advanced work on libraries.

The CircuitPython Community Library Bundle

The CircuitPython Community Library Bundle is made up of libraries written and

provided by members of the CircuitPython community. These libraries are often

written when community members encountered hardware not supported in the

Adafruit Bundle, or to support a personal project. The authors all chose to submit

these libraries to the Community Bundle make them available to the community.

These libraries are maintained by their authors and are not supported by Adafruit. As

you would with any library, if you run into problems, feel free to file an issue on the

GitHub repo for the library. Bear in mind, though, that most of these libraries are

supported by a single person and you should be patient about receiving a response.

Remember, these folks are not paid by Adafruit, and are volunteering their personal

time when possible to provide support.

Downloading the CircuitPython Community Library Bundle

You can download the latest CircuitPython Community Library Bundle release by

clicking the button below. The libraries are being constantly updated and improved,

so you'll always want to download the latest bundle.

Click for the latest CircuitPython

Community Library Bundle release

The link takes you to the latest release of the CircuitPython Community Library

Bundle on GitHub. There are multiple versions of the bundle available. Download the

bundle version that matches your CircuitPython firmware version. If you don't know

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the version, check the version info in boot_out.txt file on the CIRCUITPY drive, or the

initial prompt in the CircuitPython REPL. For example, if you're running v7.0.0,

download the 7.x library bundle.

Understanding the Bundle

After downloading the zip, extract its contents. This is usually done by double clicking

on the zip. On Mac OSX, it places the file in the same directory as the zip.

Open the bundle folder. Inside you'll find two information files, and two folders. One

folder is the lib bundle, and the other folder is the examples bundle.

Now open the lib folder. When you open the folder, you'll see a large number of .mpy

files, and folders.

Example Files

All example files from each library are now included in the bundles in an examples

directory (as seen above), as well as an examples-only bundle. These are included for

two main reasons:

Allow for quick testing of devices.

•

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Provide an example base of code, that is easily built upon for individualized

•

purposes.

Copying Libraries to Your Board

First open the lib folder on your CIRCUITPY drive. Then, open the lib folder you

extracted from the downloaded zip. Inside you'll find a number of folders and .mpy

files. Find the library you'd like to use, and copy it to the lib folder on CIRCUITPY.

If the library is a directory with multiple .mpy files in it, be sure to copy the entire

folder to CIRCUITPY/lib.

This also applies to example files. Open the examples folder you extracted from the

downloaded zip, and copy the applicable file to your CIRCUITPY drive. Then, rename

it to code.py to run it.

If a library has multiple .mpy files contained in a folder, be sure to copy the entire

folder to CIRCUITPY/lib.

Understanding Which Libraries to Install

You now know how to load libraries on to your CircuitPython-compatible

microcontroller board. You may now be wondering, how do you know which libraries

you need to install? Unfortunately, it's not always straightforward. Fortunately, there is

an obvious place to start, and a relatively simple way to figure out the rest. First up:

the best place to start.

When you look at most CircuitPython examples, you'll see they begin with one or
more import statements. These typically look like the following:

import library_or_module

•

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However, import statements can also sometimes look like the following:

from library_or_module import name

•

from library_or_module.subpackage import name

•

from library_or_module import name as local_name

•

They can also have more complicated formats, such as including a try / except

block, etc.

The important thing to know is that an import statement will always include the

name of the module or library that you're importing.

Therefore, the best place to start is by reading through the import statements.

Here is an example import list for you to work with in this section. There is no setup or

other code shown here, as the purpose of this section involves only the import list.

import time
import board
import neopixel
import adafruit_lis3dh
import usb_hid
from adafruit_hid.consumer_control import ConsumerControl
from adafruit_hid.consumer_control_code import ConsumerControlCode

Keep in mind, not all imported items are libraries. Some of them are almost always

built-in CircuitPython modules. How do you know the difference? Time to visit the

REPL.

In the Interacting with the REPL section() on The REPL page() in this guide, the

help("modules") command is discussed. This command provides a list of all of the

built-in modules available in CircuitPython for your board. So, if you connect to the
serial console on your board, and enter the REPL, you can run help("modules") to
see what modules are available for your board. Then, as you read through the impor

t statements, you can, for the purposes of figuring out which libraries to load, ignore

the statement that import modules.

The following is the list of modules built into CircuitPython for the Feather RP2040.

Your list may look similar or be anything down to a significant subset of this list for

smaller boards.

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Now that you know what you're looking for, it's time to read through the import
statements. The first two, time and board , are on the modules list above, so they're

built-in.

The next one, neopixel , is not on the module list. That means it's your first library!

So, you would head over to the bundle zip you downloaded, and search for neopixel.

There is a neopixel.mpy file in the bundle zip. Copy it over to the lib folder on your CI
RCUITPY drive. The following one, adafruit_lis3dh , is also not on the module list.

Follow the same process for adafruit_lis3dh, where you'll find adafruit_lis3dh.mpy,

and copy that over.

The fifth one is usb_hid , and it is in the modules list, so it is built in. Often all of the

built-in modules come first in the import list, but sometimes they don't! Don't assume

that everything after the first library is also a library, and verify each import with the

modules list to be sure. Otherwise, you'll search the bundle and come up empty!

The final two imports are not as clear. Remember, when import statements are
formatted like this, the first thing after the from is the library name. In this case, the
library name is adafruit_hid . A search of the bundle will find an adafruit_hid folder.

When a library is a folder, you must copy the entire folder and its contentsas it is in

the bundle to the lib folder on your CIRCUITPY drive. In this case, you would copy the

entire adafruit_hid folder to your CIRCUITPY/lib folder.

Notice that there are two imports that begin with adafruit_hid . Sometimes you will

need to import more than one thing from the same library. Regardless of how many

times you import the same library, you only need to load the library by copying over

the adafruit_hid folder once.

That is how you can use your example code to figure out what libraries to load on

your CircuitPython-compatible board!

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There are cases, however, where libraries require other libraries internally. The

internally required library is called a dependency. In the event of library

dependencies, the easiest way to figure out what other libraries are required is to
connect to the serial console and follow along with the ImportError printed there.
The following is a very simple example of an ImportError , but the concept is the

same for any missing library.

Example: ImportError Due to Missing Library

If you choose to load libraries as you need them, or you're starting fresh with an

existing example, you may end up with code that tries to use a library you haven't yet

loaded. This section will demonstrate what happens when you try to utilise a library

that you don't have loaded on your board, and cover the steps required to resolve the

issue.

This demonstration will only return an error if you do not have the required library

loaded into the lib folder on your CIRCUITPY drive.

Let's use a modified version of the Blink example.

import board
import time
import simpleio

led = simpleio.DigitalOut(board.LED)

while True:
led.value = True
time.sleep(0.5)
led.value = False
time.sleep(0.5)

Save this file. Nothing happens to your board. Let's check the serial console to see

what's going on.

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You have an ImportError . It says there is no module named 'simpleio' . That's

the one you just included in your code!

Click the link above to download the correct bundle. Extract the lib folder from the

downloaded bundle file. Scroll down to find simpleio.mpy. This is the library file you're

looking for! Follow the steps above to load an individual library file.

The LED starts blinking again! Let's check the serial console.

No errors! Excellent. You've successfully resolved an ImportError !

If you run into this error in the future, follow along with the steps above and choose

the library that matches the one you're missing.

Library Install on Non-Express Boards

If you have an M0 non-Express board such as Trinket M0, Gemma M0, QT Py M0, or

one of the M0 Trinkeys, you'll want to follow the same steps in the example above to
install libraries as you need them. Remember, you don't need to wait for an ImportEr

ror if you know what library you added to your code. Open the library bundle you

downloaded, find the library you need, and drag it to the lib folder on your CIRCUITPY

drive.

You can still end up running out of space on your M0 non-Express board even if you

only load libraries as you need them. There are a number of steps you can use to try

to resolve this issue. You'll find suggestions on the Troubleshooting page().

Updating CircuitPython Libraries and Examples

Libraries and examples are updated from time to time, and it's important to update the

files you have on your CIRCUITPY drive.

To update a single library or example, follow the same steps above. When you drag

the library file to your lib folder, it will ask if you want to replace it. Say yes. That's it!

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A new library bundle is released every time there's an update to a library. Updates

include things like bug fixes and new features. It's important to check in every so

often to see if the libraries you're using have been updated.

CircUp CLI Tool

There is a command line interface (CLI) utility called CircUp() that can be used to

easily install and update libraries on your device. Follow the directions on the install

page within the CircUp learn guide(). Once you've got it installed you run the

command circup update in a terminal to interactively update all libraries on the

connected CircuitPython device. See the usage page in the CircUp guide() for a full

list of functionality

CircuitPython Documentation

You've learned about the CircuitPython built-in modules and external libraries. You

know that you can find the modules in CircuitPython, and the libraries in the Library

Bundles. There are guides available that explain the basics of many of the modules

and libraries. However, there's sometimes more capabilities than are necessarily

showcased in the guides, and often more to learn about a module or library. So,

where can you find more detailed information? That's when you want to look at the

API documentation.

The entire CircuitPython project comes with extensive documentation available on

Read the Docs. This includes both the CircuitPython core() and the Adafruit

CircuitPython libraries().

CircuitPython Core Documentation

The CircuitPython core documentation() covers many of the details you might want to

know about the CircuitPython core and related topics. It includes API and usage info,

a design guide and information about porting CircuitPython to new boards,

MicroPython info with relation to CircuitPython, and general information about the

project.

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The main page covers the basics including where to download CircuitPython, how to

contribute, differences from MicroPython, information about the project structure, and

a full table of contents for the rest of the documentation.

The list along the left side leads to more information about specific topics.

The first section is API and Usage. This is where you can find information about how
to use individual built-in core modules, such as time and digitalio , details about

the supported ports, suggestions for troubleshooting, and basic info and links to the li

brary bundles. The Core Modules section also includes the Support Matrix, which is a

table of which core modules are available on which boards.

The second section is Design and Porting Reference. It includes a design guide, archit

ecture information, details onporting, and adding module support to other ports.

The third section is MicroPython Specific. It includes information on MicroPython and

related libraries, and a glossary of terms.

The fourth and final section is About the Project. It includes further information

including details on building, testing, and debugging CircuitPython, along with various

other useful links including the Adafruit Community Code of Conduct.

Whether you're a seasoned pro or new to electronics and programming, you'll find a

wealth of information to help you along your CircuitPython journey in the

documentation!

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CircuitPython Library Documentation

The Adafruit CircuitPython libraries are documented in a very similar fashion. Each

library has its own page on Read the Docs. There is a comprehensive list available her

e(). Otherwise, to view the documentation for a specific library, you can visit the

GitHub repository for the library, and find the link in the README.

For the purposes of this page, the LED Animation library() documentation will be

featured. There are two links to the documentation in each library GitHub repo. The

first one is the docs badge near the top of the README.

The second place is the Documentation section of the README. Scroll down to find it,

and click on Read the Docs to get to the documentation.

Now that you know how to find it, it's time to take a look at what to expect.

Not all library documentation will look exactly the same, but this will give you

some idea of what to expect from library docs.

The Introduction page is generated from the README, so it includes all the same info,

such as PyPI installation instructions, a quick demo, and some build details. It also

includes a full table of contents for the rest of the documentation (which is not part of

the GitHub README). The page should look something like the following.

The left side contains links to the rest of the documentation, divided into three

separate sections: Examples, API Reference, and Other Links.

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Examples

The Examples section() is a list of library examples. This list contains anywhere from a

small selection to the full list of the examples available for the library.

This section will always contain at least one example - the simple test example.

The simple test example is usually a basic example designed to show your setup is

working. It may require other libraries to run. Keep in mind, it's simple - it won't

showcase a comprehensive use of all the library features.

The LED Animation simple test demonstrates the Blink animation.

In some cases, you'll find a longer list, that may include examples that explore other

features in the library. The LED Animation documentation includes a series of

examples, all of which are available in the library. These examples include

demonstrations of both basic and more complex features. Simply click on the example

that interests you to view the associated code.

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When there are multiple links in the Examples section, all of the example content

is, in actuality, on the same page. Each link after the first is an anchor link to the

specified section of the page. Therefore, you can also view all the available

examples by scrolling down the page.

You can view the rest of the examples by clicking through the list or scrolling down

the page. These examples are fully working code. Which is to say, while they may rely

on other libraries as well as the library for which you are viewing the documentation,

they should not require modification to otherwise work.

API Reference

The API Reference section() includes a list of the library functions and classes. The

API (Application Programming Interface) of a library is the set of functions and classes

the library provides. Essentially, the API defines how your program interfaces with the

functions and classes that you call in your code to use the library.

There is always at least one list item included. Libraries for which the code is included

in a single Python (.py) file, will only have one item. Libraries for which the code is

multiple Python files in a directory (called subpackages) will have multiple items in this

list. The LED Animation library has a series of subpackages, and therefore, multiple

items in this list.

Click on the first item in the list to begin viewing the API Reference section.

As with the Examples section, all of the API Reference content is on a single

page, and the links under API Reference are anchor links to the specified section

of the page.

When you click on an item in the API Reference section, you'll find details about the

classes and functions in the library. In the case of only one item in this section, all the

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available functionality of the library will be contained within that first and only

subsection. However, in the case of a library that has subpackages, each item will

contain the features of the particular subpackage indicated by the link. The

documentation will cover all of the available functions of the library, including more

complex ones that may not interest you.

The first list item is the animation subpackage. If you scroll down, you'll begin to see

the available features of animation. They are listed alphabetically. Each of these

things can be called in your code. It includes the name and a description of the

specific function you would call, and if any parameters are necessary, lists those with

a description as well.

You can view the other subpackages by clicking the link on the left or scrolling down

the page. You may be interested in something a little more practical. Here is an

example. To use the LED Animation library Comet animation, you would run the

following example.

# SPDX-FileCopyrightText: 2021 Kattni Rembor for Adafruit Industries
# SPDX-License-Identifier: MIT

"""
This example animates a jade comet that bounces from end to end of the strip.

For QT Py Haxpress and a NeoPixel strip. Update pixel_pin and pixel_num to match
your wiring if
using a different board or form of NeoPixels.

This example will run on SAMD21 (M0) Express boards (such as Circuit Playground
Express or QT Py
Haxpress), but not on SAMD21 non-Express boards (such as QT Py or Trinket).
"""
import board
import neopixel

from adafruit_led_animation.animation.comet import Comet
from adafruit_led_animation.color import JADE

# Update to match the pin connected to your NeoPixels
pixel_pin = board.A3
# Update to match the number of NeoPixels you have connected
pixel_num = 30

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pixels = neopixel.NeoPixel(pixel_pin, pixel_num, brightness=0.5, auto_write=False)

comet = Comet(pixels, speed=0.02, color=JADE, tail_length=10, bounce=True)

while True:
comet.animate()

Note the line where you create the comet object. There are a number of items inside

the parentheses. In this case, you're provided with a fully working example. But what

if you want to change how the comet works? The code alone does not explain what

the options mean.

So, in the API Reference documentation list, click the

adafruit_led_animation.animation.comet link and scroll down a bit until you

see the following.

Look familiar? It is! This is the documentation for setting up the comet object. It

explains what each argument provided in the comet setup in the code meant, as well
as the other available features. For example, the code includes speed=0.02 . The

documentation clarifies that this is the "Animation speed in seconds". The code
doesn't include ring . The documentation indicates this is an available setting that

enables "Ring mode".

This type of information is available for any function you would set up in your code. If

you need clarification on something, wonder whether there's more options available,

or are simply interested in the details involved in the code you're writing, check out

the documentation for the CircuitPython libraries!

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Other Links

This section is the same for every library. It includes a list of links to external sites,

which you can visit for more information about the CircuitPython Project and Adafruit.

That covers the CircuitPython library documentation! When you are ready to go

beyond the basic library features covered in a guide, or you're interested in

understanding those features better, the library documentation on Read the Docs has

you covered!

Recommended Editors

The CircuitPython code on your board detects when the files are changed or written

and will automatically re-start your code. This makes coding very fast because you

save, and it re-runs.

However, you must wait until the file is done being saved before unplugging or

resetting your board! On Windows using some editors this can sometimes take up to

90 seconds, on Linux it can take 30 seconds to complete because the text editor

does not save the file completely. Mac OS does not seem to have this delay, which is

nice!

This is really important to be aware of. If you unplug or reset the board before your

computer finishes writing the file to your board, you can corrupt the drive. If this

happens, you may lose the code you've written, so it's important to backup your code

to your computer regularly.

To avoid the likelihood of filesystem corruption, use an editor that writes out the file

completely when you save it. Check out the list of recommended editors below.

Recommended editors

mu() is an editor that safely writes all changes (it's also our recommended

•

editor!)

emacs() is also an editor that will fulIy write files on save()

•

Sublime Text()safelywrites all changes

•

Visual Studio Code() appears to safely write all changes

•

gedit on Linux appears to safely write all changes

•

IDLE(), in Python 3.8.1 or later, was fixed() to write all changes immediately

•

Thonny() fully writes files on save

•

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Recommended only with particular settings or add-ons

vim()/visafely writes all changes. But set upvimto not write swapfiles() (.swp

•

files: temporary records of your edits) to CIRCUITPY. Run vim with vim -n ,set
the no swapfile option, or set the directory option to write swapfiles

elsewhere. Otherwise the swapfile writestrigger restarts of your program.

ThePyCharm IDE()is safe if "Safe Write" is turned on in Settings->System

•

Settings->Synchronization (true by default).

If you are usingAtom(), install thefsync-on-save package() or the language-

•

circuitpython package() so that it will always write out all changes to files on CIR

CUITPY.

SlickEdit()works only if youadd a macro to flush the disk().

•

The editors listed below are specifically NOT recommended!

Editors that are NOT recommended

notepad (the default Windows editor) and Notepad++ can be slow to write, so

•

the editors above are recommended! If you are using notepad, be sure to eject

the drive.

IDLE in Python 3.8.0 or earlier does not force out changes immediately.

•

nano (on Linux) does not force out changes.

•

geany (on Linux) does not force out changes.

•

Anything else - Other editors have not been tested so please use a

•

recommended one!

Advanced Serial Console on Windows

Windows 7 and 8.1

If you're using Windows 7 (or 8 or 8.1), you'll need to install drivers. See the Windows 7

and 8.1 Drivers page() for details. You will not need to install drivers on Mac, Linux or

Windows 10.

You are strongly encouraged to upgrade to Windows 10 if you are still using Windows

7 or Windows 8 or 8.1. Windows 7 has reached end-of-life and no longer receives

security updates. A free upgrade to Windows 10 is still available().

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What's the COM?

First, you'll want to find out which serial port your board is using. When you plug your

board in to USB on your computer, it connects to a serial port. The port is like a door

through which your board can communicate with your computer using USB.

You'll use Windows Device Manager to determine which port the board is using. The

easiest way to determine which port the board is using is to first check without the

board plugged in. Open Device Manager. Click on Ports (COM & LPT). You should find

something already in that list with (COM#) after it where # is a number.

Now plug in your board. The Device Manager list will refresh and a new item will

appear under Ports (COM & LPT). You'll find a different (COM#) after this item in the

list.

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Sometimes the item will refer to the name of the board. Other times it may be called

something like USB Serial Device, as seen in the image above. Either way, there is a

new (COM#) following the name. This is the port your board is using.

Install Putty

If you're using Windows, you'll need to download a terminal program. You're going to

use PuTTY.

The first thing to do is download the latest version of PuTTY(). You'll want to

download the Windows installer file. It is most likely that you'll need the 64-bit version.

Download the file and install the program on your machine. If you run into issues, you

can try downloading the 32-bit version instead. However, the 64-bit version will work

on most PCs.

Now you need to open PuTTY.

Under Connection type: choose the button next to Serial.

•

In the box under Serial line, enter the serial port you found that your board is

•

using.

In the box under Speed, enter 115200. This called the baud rate, which is the

•

speed in bits per second that data is sent over the serial connection. For boards

with built in USB it doesn't matter so much but for ESP8266 and other board

with a separate chip, the speed required by the board is 115200 bits per second.

So you might as well just use 115200!

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If you want to save those settings for later, use the options under Load, save or delete

a stored session. Enter a name in the box under Saved Sessions, and click the Save

button on the right.

Once your settings are entered, you're ready to connect to the serial console. Click

"Open" at the bottom of the window. A new window will open.

If no code is running, the window will either be blank or will look like the window

above. Now you're ready to see the results of your code.

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Great job! You've connected to the serial console!

Advanced Serial Console on Mac

Connecting to the serial console on Mac does not require installing any drivers or
extra software. You'll use a terminal program to find your board, and screen to
connect to it. Terminal and screen both come installed by default.

What's the Port?

First you'll want to find out which serial port your board is using. When you plug your

board in to USB on your computer, it connects to a serial port. The port is like a door

through which your board can communicate with your computer using USB.

The easiest way to determine which port the board is using is to first check without

the board plugged in. Open Terminal and type the following:

ls /dev/tty.*

Each serial connection shows up in the /dev/ directory. It has a name that starts with

tty. . The command ls shows you a list of items in a directory. You can use * as a

wildcard, to search for files that start with the same letters but end in something
different. In this case, you're asking to see all of the listings in /dev/ that start with t

ty. and end in anything. This will show us the current serial connections.

Now, plug your board. In Terminal, type:

ls /dev/tty.*

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This will show you the current serial connections, which will now include your board.

A new listing has appeared called /dev/tty.usbmodem141441 . The tty.usbmodem1

41441 part of this listing is the name the example board is using. Yours will be called

something similar.

Using Linux, a new listing has appeared called /dev/ttyACM0 . The ttyACM0 part of

this listing is the name the example board is using. Yours will be called something

similar.

Connect with screen

Now that you know the name your board is using, you're ready connect to the serial
console. You're going to use a command called screen . The screen command is

included with MacOS. To connect to the serial console, use Terminal. Type the
following command, replacing board_name with the name you found your board is

using:

screen /dev/tty.board_name 115200

The first part of this establishes using the screen command. The second part tells

screen the name of the board you're trying to use. The third part tells screen what

baud rate to use for the serial connection. The baud rate is the speed in bits per

second that data is sent over the serial connection. In this case, the speed required

by the board is 115200 bits per second.

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Press enter to run the command. It will open in the same window. If no code is

running, the window will be blank. Otherwise, you'll see the output of your code.

Great job! You've connected to the serial console!

Advanced Serial Console on Linux

Connecting to the serial console on Linux does not require installing any drivers, but
you may need to install screen using your package manager. You'll use a terminal
program to find your board, and screen to connect to it. There are a variety of

terminal programs such as gnome-terminal (called Terminal) or Konsole on KDE.

The tio program works as well to connect to your board, and has the benefit of

automatically reconnecting. You would need to install it using your package manager.

What's the Port?

First you'll want to find out which serial port your board is using. When you plug your

board in to USB on your computer, it connects to a serial port. The port is like a door

through which your board can communicate with your computer using USB.

The easiest way to determine which port the board is using is to first check without

the board plugged in. Open your terminal program and type the following:

ls /dev/ttyACM*

Each serial connection shows up in the /dev/ directory. It has a name that starts with tt
yACM. The command ls shows you a list of items in a directory. You can use * as a

wildcard, to search for files that start with the same letters but end in something

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different. In this case, You're asking to see all of the listings in /dev/ that start with ttyA

CM and end in anything. This will show us the current serial connections.

In the example below, the error is indicating that are no current serial connections

starting with ttyACM.

Now plug in your board. In your terminal program, type:

ls /dev/ttyACM*

This will show you the current serial connections, which will now include your board.

A new listing has appeared called /dev/ttyACM0. The ttyACM0 part of this listing is

the name the example board is using. Yours will be called something similar.

Connect with screen

Now that you know the name your board is using, you're ready connect to the serial
console. You'll use a command called screen . You may need to install it using the

package manager.

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To connect to the serial console, use your terminal program. Type the following
command, replacing board_name with the name you found your board is using:

screen /dev/tty.board_name 115200

The first part of this establishes using the screen command. The second part tells

screen the name of the board you're trying to use. The third part tells screen what

baud rate to use for the serial connection. The baud rate is the speed in bits per

second that data is sent over the serial connection. In this case, the speed required

by the board is 115200 bits per second.

Press enter to run the command. It will open in the same window. If no code is

running, the window will be blank. Otherwise, you'll see the output of your code.

Great job! You've connected to the serial console!

Permissions on Linux

If you try to run screen and it doesn't work, then you may be running into an issue

with permissions. Linux keeps track of users and groups and what they are allowed to

do and not do, like access the hardware associated with the serial connection for
running screen . So if you see something like this:

then you may need to grant yourself access. There are generally two ways you can do
this. The first is to just run screen using the sudo command, which temporarily

gives you elevated privileges.

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Once you enter your password, you should be in:

The second way is to add yourself to the group associated with the hardware. To
figure out what that group is, use the command ls -l as shown below. The group

name is circled in red.

Then use the command adduser to add yourself to that group. You need elevated
privileges to do this, so you'll need to use sudo . In the example below, the group is a

dm and the user is ackbar.

After you add yourself to the group, you'll need to logout and log back in, or in some

cases, reboot your machine. After you log in again, verify that you have been added
to the group using the command groups . If you are still not in the group, reboot and

check again.

And now you should be able to run screen without using sudo .

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And you're in:

The examples above use screen , but you can also use other programs, such as put

ty or picocom , if you prefer.

Frequently Asked Questions

These are some of the common questions regarding CircuitPython and CircuitPython

microcontrollers.

What are some common acronyms to know?

CP or CPy = CircuitPython()

CPC = Circuit Playground Classic()(does not run CircuitPython)

CPX = Circuit Playground Express()

CPB = Circuit Playground Bluefruit()

Using Older Versions

As CircuitPython development continues and there are new releases, Adafruit

will stop supporting older releases. Visit https://circuitpython.org/downloads to

download the latest version of CircuitPython for your board. You must download

the CircuitPython Library Bundle that matches your version of CircuitPython.

Please update CircuitPython and then visit https://circuitpython.org/libraries to

download the latest Library Bundle.

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I have to continue using CircuitPython 7.x or earlier. Where can I find compatible libraries?

We are no longer building or supporting the CircuitPython 7.x or earlier library

bundles. We highly encourage you to update CircuitPython to the latest version()

and use the current version of the libraries(). However, if for some reason you

cannot update, here are the last available library bundles for older versions:

2.x bundle()

•

3.x bundle()

•

4.x bundle()

•

5.x bundle()

•

6.x bundle()

•

7.x bundle()

•

Python Arithmetic

Does CircuitPython support floating-point numbers?

All CircuitPython boards support floating point arithmetic, even if the

microcontroller chip does not support floating point in hardware. Floating point

numbers are stored in 30 bits, with an 8-bit exponent and a 22-bit mantissa. Note

that this is two bits less than standard 32-bit single-precision floats. You will get

about 5-1/2 digits of decimal precision.

(Thebroadcomport may provide 64-bit floats in some cases.)

Does CircuitPython support long integers, like regular Python?

Python long integers (integers of arbitrary size) are available on most builds, except

those on boards with the smallest available firmware size. On these boards,

integers are stored in 31 bits.

Boards without long integer support are mostly SAMD21 ("M0") boards without an

external flash chip, such as the Adafruit Gemma M0, Trinket M0, QT Py M0, and the

Trinkey series. There are also a number of third-party boards in this category.

There are also a few small STM third-party boards without long integer support.

time.localtime() , time.mktime() , time.time() , and
time.monotonic_ns() are available only on builds with long integers.

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Wireless Connectivity

How do I connect to the Internet with CircuitPython?

If you'd like to include WiFi in your project, your best bet is to use a board that is

running natively on ESP32 chipsets - those have WiFi built in!

If your development board has an SPI port and at least 4 additional pins, you can

check out this guide() on using AirLift with CircuitPython - extra wiring is required

and some boards like the MacroPad or NeoTrellis do not have enough available

pins to add the hardware support.

For further project examples, and guides about using AirLift with specific hardware,

check out the Adafruit Learn System().

How do I do BLE (Bluetooth Low Energy) with CircuitPython?

The nRF52840 and nRF52833 boards have the most complete BLE

implementation. Your program can act as both a BLE central and peripheral. As a

central, you can scan for advertisements, and connect to an advertising board. As a

peripheral, you can advertise, and you can create services available to a central.

Pairing and bonding are supported.

ESP32-C3 and ESP32-S3 boards currently provide an incomplete()BLE

implementation. Your program can act as a central, and connect to a peripheral.

You can advertise, but you cannot create services. You cannot advertise

anonymously. Pairing and bonding are not supported.

The ESP32 could provide a similar implementation, but it is not yet available. Note

that the ESP32-S2 does not have Bluetooth capability.

On most other boards with adequate firmware space, BLE is available for use with

AirLift() or other NINA-FW-based co-processors. Some boards have this

coprocessor on board, such as the PyPortal(). Currently, this implementation only

supports acting as a BLE peripheral. Scanning and connecting as a central are not

yet implemented. Bonding and pairing are not supported.

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Are there other ways to communicate by radio with CircuitPython?

Check out Adafruit's RFM boards ()for simple radio communication supported by

CircuitPython, which can be used over distances of 100m to over a km, depending

on the version. The RFM SAMD21 M0 boards can be used, but they were not

designed for CircuitPython, and have limited RAM and flash space; using the RFM

breakouts or FeatherWings with more capable boards will be easier.

Asyncio and Interrupts

Is there asyncio support in CircuitPython?

There is support for asyncio starting with CircuitPython 7.1.0, on all boards except

the smallest SAMD21 builds. Read about using it in the Cooperative Multitasking in

CircuitPython() Guide.

Does CircuitPython support interrupts?

No. CircuitPython does not currently support interrupts - please use asyncio for

multitasking / 'threaded' control of your code

Status RGB LED

My RGB NeoPixel/DotStar LED is blinking funny colors ­what does it mean?

The status LED can tell you what's going on with your CircuitPython board. Read

more here for what the colors mean!()

Memory Issues

What is a MemoryError?

Memory allocation errors happen when you're trying to store too much on the

board. The CircuitPython microcontroller boards have a limited amount of memory

available. You can have about 250 lines of code on the M0 Express boards. If you
try to import too many libraries, a combination of large libraries, or run a program

with too many lines of code, your code will fail to run and you will receive a

MemoryError in the serial console.

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What do I do when I encounter a MemoryError?

Try resetting your board. Each time you reset the board, it reallocates the memory.

While this is unlikely to resolve your issue, it's a simple step and is worth trying.

Make sure you are using .mpy versions of libraries. All of the CircuitPython libraries

are available in the bundle in a .mpy format which takes up less memory than .py

format. Be sure that you're using the latest library bundle() for your version of

CircuitPython.

If that does not resolve your issue, try shortening your code. Shorten comments,

remove extraneous or unneeded code, or any other clean up you can do to

shorten your code. If you're using a lot of functions, you could try moving those

into a separate library, creating a .mpy of that library, and importing it into your

code.

You can turn your entire file into a .mpy and import that into code.py. This means

you will be unable to edit your code live on the board, but it can save you space.

Can the order of my import statements affect memory?

It can because the memory gets fragmented differently depending on allocation

order and the size of objects. Loading .mpy files uses less memory so its

recommended to do that for files you aren't editing.

How can I create my own .mpy files?

You can make your own .mpy versions of files with mpy-cross .

You can download mpy-cross for your operating system from here(). Builds are

available for Windows, macOS, x64 Linux, and Raspberry Pi Linux. Choose the
latest mpy-cross whose version matches the version of CircuitPython you are

using.

To make a .mpy file, run ./mpy-cross path/to/yourfile.py to create a

yourfile.mpy in the same directory as the original file.

How do I check how much memory I have free?

Run the following to see the number of bytes available for use:

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import gc
gc.mem_free()

Unsupported Hardware

Is ESP8266 or ESP32 supported in CircuitPython? Why not?

We dropped ESP8266 support as of 4.x - For more information please read about it

here()!

As of CircuitPython 8.x we have started to support ESP32 and ESP32-C3 and have

added a WiFi workflow for wireless coding!()

We also support ESP32-S2 & ESP32-S3, which have native USB.

Does Feather M0 support WINC1500?

No, WINC1500 will not fit into the M0 flash space.

Can AVRs such as ATmega328 or ATmega2560 run CircuitPython?

No.

Troubleshooting

From time to time, you will run into issues when working with CircuitPython. Here are

a few things you may encounter and how to resolve them.

As CircuitPython development continues and there are new releases, Adafruit

will stop supporting older releases. Visit https://circuitpython.org/downloads to

download the latest version of CircuitPython for your board. You must download

the CircuitPython Library Bundle that matches your version of CircuitPython.

Please update CircuitPython and then visit https://circuitpython.org/libraries to

download the latest Library Bundle.

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Always Run the Latest Version of CircuitPython and Libraries

As CircuitPython development continues and there are new releases, Adafruit will

stop supporting older releases. You need to update to the latest CircuitPython.().

You need to download the CircuitPython Library Bundle that matches your version of

CircuitPython. Please update CircuitPython and then download the latest bundle().

As new versions of CircuitPython are released, Adafruit will stop providing the

previous bundles as automatically created downloads on the Adafruit CircuitPython

Library Bundle repo. If you must continue to use an earlier version, you can still
download the appropriate version of mpy-cross from the particular release of

CircuitPython on the CircuitPython repo and create your own compatible .mpy library

files. However, it is best to update to the latest for both CircuitPython and the library

bundle.

I have to continue using CircuitPython 7.x or earlier. Where can I find compatible libraries?

Adafruit is no longer building or supporting the CircuitPython 7.x or earlier library

bundles. You are highly encourged to update CircuitPython to the latest version() and

use the current version of the libraries(). However, if for some reason you cannot

update, links to the previous bundles are available in the FAQ().

Bootloader (boardnameBOOT) Drive Not Present

You may have a different board.

Only Adafruit Express boards and the SAMD21 non-Express boards ship with the UF2

bootloader ()installed. The Feather M0 Basic, Feather M0 Adalogger, and similar

boards use a regular Arduino-compatible bootloader, which does not show a boardna

meBOOT drive.

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MakeCode

If you are running a MakeCode() program on Circuit Playground Express, press the

reset button just onceto get the CPLAYBOOT drive to show up. Pressing it twice will

not work.

macOS

DriveDx and its accompanything SAT SMART Driver can interfere with seeing the

BOOT drive. See this forum post() for how to fix the problem.

Windows 10

Did you install the Adafruit Windows Drivers package by mistake, or did you upgrade

to Windows 10 with the driver package installed? You don't need to install this

package on Windows 10 for most Adafruit boards. The old version (v1.5) can interfere

with recognizing your device. Go to Settings -> Apps and uninstall all the "Adafruit"

driver programs.

Windows 7 or 8.1

To use a CircuitPython-compatible board with Windows 7 or 8.1, you must install a

driver. Installation instructions are available here().

It is recommended() that you upgrade to Windows 10 if possible; an upgrade is

probably still free for you. Check here().

The Windows Drivers installer was last updated in November 2020 (v2.5.0.0) .

Windows 7 drivers for CircuitPython boards released since then, including

RP2040 boards, are not available. There are no plans to release drivers for new

boards. The boards work fine on Windows 10.

You should now be done! Test by unplugging and replugging the board. You should

see the CIRCUITPY drive, and when you double-click the reset button (single click on

Circuit Playground Express running MakeCode), you should see the appropriateboar

dnameBOOT drive.

Let us know in the Adafruit support forums() or on the Adafruit Discord() if this does

not work for you!

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Windows Explorer Locks Up When Accessing boardnameBOOT Drive

On Windows, several third-party programs that can cause issues. The symptom is that

you try to access the boardnameBOOTdrive, and Windows or Windows Explorer

seems to lock up. These programs are known to cause trouble:

AIDA64: to fix, stop the program. This problem has been reported to AIDA64.

•

They acquired hardware to test, and released a beta version that fixes the

problem. This may have been incorporated into the latest release. Please let us

know in the forums if you test this.

Hard Disk Sentinel

•

Kaspersky anti-virus: To fix, you may need to disable Kaspersky completely.

•

Disabling some aspects of Kaspersky does not always solve the problem. This

problem has been reported to Kaspersky.

ESET NOD32 anti-virus: There have been problems with at least version

•

9.0.386.0, solved by uninstallation.

Copying UF2 to boardnameBOOT Drive Hangs at 0% Copied

On Windows, a Western DIgital (WD) utility that comes with their external USB drives

can interfere with copying UF2 files to the boardnameBOOT drive. Uninstall that utility

to fix the problem.

CIRCUITPY Drive Does Not Appear or Disappears Quickly

Kaspersky anti-virus can block the appearance of the CIRCUITPY drive. There has not

yet been settings change discovered that prevents this. Complete uninstallation of

Kaspersky fixes the problem.

Norton anti-virus can interfere with CIRCUITPY. A user has reported this problem on

Windows 7. The user turned off both Smart Firewall and Auto Protect, and CIRCUITPY

then appeared.

Sophos Endpoint security software can cause CIRCUITPY to disappear() and the

BOOT drive to reappear. It is not clear what causes this behavior.

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Samsung Magician can cause CIRCUITPY to disappear (reported here() and here()).

Device Errors or Problems on Windows

Windows can become confused about USB device installations. This is particularly

true of Windows 7 and 8.1. It is recommended() that you upgrade to Windows 10 if

possible; an upgrade is probably still free for you: see this link().

If not, try cleaning up your USB devices. Use Uwe Sieber's Device Cleanup Tool()(on

that page, scroll down to "Device Cleanup Tool"). Download and unzip the tool.

Unplug all the boards and other USB devices you want to clean up. Run the tool as

Administrator. You will see a listing like this, probably with many more devices. It is

listing all the USB devices that are not currently attached.

Select all the devices you want to remove, and then press Delete. It is usually safe

just to select everything. Any device that is removed will get a fresh install when you

plug it in. Using the Device Cleanup Tool also discards all the COM port assignments

for the unplugged boards. If you have used many Arduino and CircuitPython boards,

you have probably seen higher and higher COM port numbers used, seemingly

without end. This will fix that problem.

Serial Console in Mu Not Displaying Anything

There are times when the serial console will accurately not display anything, such as,

when no code is currently running, or when code with no serial output is already

running before you open the console. However, if you find yourself in a situation

where you feel it should be displaying something like an error, consider the following.

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Depending on the size of your screen or Mu window, when you open the serial

console, the serial console panel may be very small. This can be a problem. A basic

CircuitPython error takes 10 lines to display!

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
Traceback (most recent call last):
File "code.py", line 7
SyntaxError: invalid syntax

Press any key to enter the REPL. Use CTRL-D to reload.

More complex errors take even more lines!

Therefore, if your serial console panel is five lines tall or less, you may only see blank
lines or blank lines followed by Press any key to enter the REPL. Use CTRL-D

to reload. . If this is the case, you need to either mouse over the top of the panel to

utilise the option to resize the serial panel, or use the scrollbar on the right side to

scroll up and find your message.

This applies to any kind of serial output whether it be error messages or print

statements. So before you start trying to debug your problem on the hardware side,

be sure to check that you haven't simply missed the serial messages due to serial

output panel height.

code.py Restarts Constantly

CircuitPython will restart code.py if you or your computer writes to something on the

CIRCUITPY drive. This feature is called auto-reload, and lets you test a change to your

program immediately.

Some utility programs, such as backup, anti-virus, or disk-checking apps, will write to

the CIRCUITPY as part of their operation. Sometimes they do this very frequently,

causing constant restarts.

Acronis True Image and related Acronis programs on Windows are known to cause

this problem. It is possible to prevent this by disabling the "()Acronis Managed

Machine Service Mini"().

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If you cannot stop whatever is causing the writes, you can disable auto-reload by

putting this code in boot.py or code.py:

import supervisor

supervisor.runtime.autoreload = False

CircuitPython RGB Status Light

Nearly all CircuitPython-capable boards have a single NeoPixel or DotStar RGB LED

on the board that indicates the status of CircuitPython. A few boards designed before

CircuitPython existed, such as the Feather M0 Basic, do not.

Circuit Playground Express and Circuit Playground Bluefruit have multiple RGB LEDs,

but do NOT have a status LED. The LEDs are all green when in the bootloader. In

versions before 7.0.0, they do NOT indicate any status while running CircuitPython.

CircuitPython 7.0.0 and Later

The status LED blinks were changed in CircuitPython 7.0.0 in order to save battery

power and simplify the blinks. These blink patterns will occur on single color LEDs

when the board does not have any RGB LEDs. Speed and blink count also vary for

this reason.

On start up, the LED will blink YELLOW multiple times for 1 second. Pressing the

RESET button (or on Espressif, the BOOT button) during this time will restart the board

and then enter safe mode. On Bluetooth capable boards, after the yellow blinks, there

will be a set of faster blue blinks. Pressing reset during the BLUE blinks will clear

Bluetooth information and start the device in discoverable mode, so it can be used

with a BLE code editor.

Once started, CircuitPython will blink a pattern every 5 seconds when no user code is

running to indicate why the code stopped:

1 GREEN blink: Code finished without error.

•

2 RED blinks:Code ended due to an exception. Check the serial console for

•

details.

3 YELLOW blinks:CircuitPython is in safe mode. No user code was run. Check

•

the serial console for safe mode reason.

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When in the REPL, CircuitPython will set the status LED to WHITE. You can change the

LED color from the REPL. The status indicator will not persist on non-NeoPixel or

DotStar LEDs.

CircuitPython 6.3.0 and earlier

Here's what the colors and blinking mean:

steady GREEN: code.py (or code.txt, main.py, or main.txt) is running

•

pulsing GREEN: code.py (etc.) has finished or does not exist

•

steady YELLOW at start up: (4.0.0-alpha.5 and newer) CircuitPython is waiting for

•

a reset to indicate that it should start in safe mode

pulsing YELLOW: Circuit Python is in safe mode: it crashed and restarted

•

steady WHITE: REPL is running

•

steady BLUE: boot.py is running

•

Colors with multiple flashes following indicate a Pythonexception and then indicate

the line number of the error. The color of the first flash indicates the type of error:

GREEN:IndentationError

•

CYAN:SyntaxError

•

WHITE: NameError

•

ORANGE: OSError

•

PURPLE: ValueError

•

YELLOW: other error

•

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These are followed by flashes indicating the line number, including place value. WHIT

E flashes are thousands' place, BLUE are hundreds' place, YELLOW are tens' place,

and CYAN are one's place. So for example, an error on line 32 would flash YELLOW

three times and then CYAN two times. Zeroes are indicated by an extra-long dark gap.

Serial console showing ValueError:

Incompatible .mpy file

This error occurs when importing a module that is stored as a .mpy binary file that

was generated by a different version of CircuitPython than the one its being loaded

into. In particular, the mpy binary format changed between CircuitPython versions 6.x

and 7.x, 2.x and 3.x, and 1.x and 2.x.

So, for instance, if you upgraded to CircuitPython 7.x from 6.x you’ll need to download
a newer version of the library that triggered the error on import . All libraries are

available in the Adafruit bundle().

CIRCUITPY Drive Issues

You may find that you can no longer save files to your CIRCUITPY drive. You may find

that your CIRCUITPY stops showing up in your file explorer, or shows up as NO_NAM

E. These are indicators that your filesystem has issues. When the CIRCUITPY disk is

not safely ejected before being reset by the button or being disconnected from USB,

it may corrupt the flash drive. It can happen on Windows, Mac or Linux, though it is

more common on Windows.

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Be aware, if you have used Arduino to program your board, CircuitPython is no longer

able to provide the USB services. You will need to reload CircuitPython to resolve this

situation.

The easiest first step is to reload CircuitPython. Double-tap reset on the board so you

get a boardnameBOOT drive rather than a CIRCUITPY drive, and copy the latest

version of CircuitPython (.uf2) back to the board. This may restore CIRCUITPY

functionality.

If reloading CircuitPython does not resolve your issue, the next step is to try putting

the board into safe mode.

Safe Mode

Whether you've run into a situation where you can no longer edit your code.py on

your CIRCUITPY drive, your board has gotten into a state where CIRCUITPY is read-

only, or you have turned off the CIRCUITPY drive altogether, safe mode can help.

Safe mode in CircuitPython does not run any user code on startup, and disables auto-

reload. This means a few things. First, safe mode bypasses any code in boot.py

(where you can set CIRCUITPY read-only or turn it off completely). Second, it does not

run the code in code.py. And finally, it does not automatically soft-reload when data is

written to the CIRCUITPY drive.

Therefore, whatever you may have done to put your board in a non-interactive state,

safe mode gives you the opportunity to correct it without losing all of the data on the

CIRCUITPY drive.

Entering Safe Mode in CircuitPython 7.x and Later

To enter safe mode when using CircuitPython 7.x, plug in your board or hit reset

(highlighted in red above). Immediately after the board starts up or resets, it waits

1000ms. On some boards, the onboard status LED will blink yellow during that time. If

you press reset during that 1000ms, the board will start up in safe mode. It can be

difficult to react to the yellow LED, so you may want to think of it simply as a "slow"

double click of the reset button. (Remember, a fast double click of reset enters the

bootloader.)

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Entering Safe Mode in CircuitPython 6.x

To enter safe mode when using CircuitPython 6.x, plug in your board or hit reset

(highlighted in red above). Immediately after the board starts up or resets, it waits

700ms. On some boards, the onboard status LED (highlighted in green above) will

turn solid yellow during this time. If you press reset during that 700ms, the board will

start up in safe mode. It can be difficult to react to the yellow LED, so you may want to

think of it simply as a slow double click of the reset button. (Remember, a fast double

click of reset enters the bootloader.)

In Safe Mode

Once you've entered safe mode successfully in CircuitPython 6.x, the LED will pulse

yellow.

If you successfully enter safe mode on CircuitPython 7.x, the LED will intermittently

blink yellow three times.

If you connect to the serial console, you'll find the following message.

Auto-reload is off.
Running in safe mode! Not running saved code.

CircuitPython is in safe mode because you pressed the reset button during boot.
Press again to exit safe mode.

Press any key to enter the REPL. Use CTRL-D to reload.

You can now edit the contents of the CIRCUITPY drive. Remember, your code will not

run until you press the reset button, or unplug and plug in your board, to get out of

safe mode.

At this point, you'll want to remove any user code incode.py and, if present, the boot.

py file from CIRCUITPY. Once removed, tap the reset button, or unplug and plug in

your board, to restart CircuitPython. This will restart the board and may resolve your

drive issues. If resolved, you can begin coding again as usual.

If safe mode does not resolve your issue, the board must be completely erased and

CircuitPython must be reloaded onto the board.

You WILL lose everything on the board when you complete the following steps. If

possible, make a copy of your code before continuing.

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To erase CIRCUITPY: storage.erase_filesystem()

CircuitPython includes a built-in function to erase and reformat the filesystem. If you

have a version of CircuitPython older than 2.3.0 on your board, you can update to the

newest version() to do this.

Connect to the CircuitPython REPL()using Mu or a terminal program.

1.

Type the following into the REPL:

2.

>>> import storage
>>> storage.erase_filesystem()

CIRCUITPY will be erased and reformatted, and your board will restart. That's it!

Erase CIRCUITPY Without Access to the REPL

If you can't access the REPL, or you're running a version of CircuitPython previous to

2.3.0 and you don't want to upgrade, there are options available for some specific

boards.

The options listed below are considered to be the "old way" of erasing your board.

The method shown above using the REPL is highly recommended as the best method

for erasing your board.

If at all possible, it is recommended to use the REPL to erase your CIRCUITPY

drive. The REPL method is explained above.

For the specific boards listed below:

If the board you are trying to erase is listed below, follow the steps to use the file to

erase your board.

 1. Download the correct erase file:

Circuit Playground Express

Feather M0 Express

Feather M4 Express

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Metro M0 Express

Metro M4 Express QSPI Eraser

Trellis M4 Express (QSPI)

Grand Central M4 Express (QSPI)

PyPortal M4 Express (QSPI)

Circuit Playground Bluefruit (QSPI)

Monster M4SK (QSPI)

PyBadge/PyGamer QSPI Eraser.UF2

CLUE_Flash_Erase.UF2

Matrix_Portal_M4_(QSPI).UF2

RP2040 boards (flash_nuke.uf2)

 2. Double-click the reset button on the board to bring up the boardnameBOOT

drive.

 3. Drag the erase .uf2 file to theboardnameBOOT drive.

 4. The status LED will turn yellow or blue, indicating the erase has started.

 5. After approximately 15 seconds, the status LED will light up green. On the

NeoTrellis M4 this is the first NeoPixel on the grid

 6. Double-click the reset button on the board to bring up theboardnameBOOTd

rive.

 7. Drag the appropriate latest release of CircuitPython() .uf2 file to theboardnam

eBOOTdrive.

It should reboot automatically and you should see CIRCUITPY in your file explorer

again.

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If the LED flashes red during step 5, it means the erase has failed. Repeat the steps

starting with 2.

If you haven't already downloaded the latest release of CircuitPython for your board,

check out the installation page(). You'll also need to load your code and reinstall your

libraries!

For SAMD21 non-Express boards that have a UF2 bootloader:

Any SAMD21-based microcontroller that does not have external flash available is

considered a SAMD21 non-Express board. Non-Express boards that have a UF2

bootloader include Trinket M0, GEMMA M0, QT Py M0, and the SAMD21-based

Trinkey boards.

If you are trying to erase a SAMD21 non-Express board, follow these steps to erase

your board.

 1. Download the erase file:

SAMD21 non-Express Boards

 2. Double-click the reset button on the board to bring up the boardnameBOOT

drive.

 3. Drag the erase .uf2 file to the boardnameBOOT drive.

 4. The boot LED will start flashing again, and the boardnameBOOT drive will

reappear.

 5. Drag the appropriate latest release CircuitPython() .uf2 file to the

boardnameBOOT drive.

It should reboot automatically and you should see CIRCUITPY in your file explorer

again.

If you haven't already downloaded the latest release of CircuitPython for your board,

check out the installation page() YYou'll also need to load your code and reinstall

your libraries!

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For SAMD21 non-Express boards that do not have a UF2 bootloader:

Any SAMD21-based microcontroller that does not have external flash available is

considered a SAMD21 non-Express board. Non-Express boards that do not have a

UF2 bootloader include the Feather M0 Basic Proto, Feather Adalogger, or the

Arduino Zero.

If you are trying to erase a non-Express board that does not have a UF2 bootloader, f

ollow these directions toreload CircuitPython using bossac (), which will erase and

re-create CIRCUITPY.

Running Out of File Space on SAMD21 Non­Express Boards

Any SAMD21-based microcontroller that does not have external flash available is

considered a SAMD21 non-Express board. This includes boards like the Trinket M0,

GEMMA M0, QT Py M0, and the SAMD21-based Trinkey boards.

The file system on the board is very tiny. (Smaller than an ancient floppy disk.) So, its

likely you'll run out of space but don't panic! There are a number of ways to free up

space.

Delete something!

The simplest way of freeing up space is to delete files from the drive. Perhaps there

are libraries in the lib folder that you aren't using anymore or test code that isn't in

use. Don't delete the lib folder completely, though, just remove what you don't need.

The board ships with the Windows 7 serial driver too! Feel free to delete that if you

don't need it or have already installed it. It's ~12KiB or so.

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Use tabs

One unique feature of Python is that the indentation of code matters. Usually the

recommendation is to indent code with four spaces for every indent. In general, that

is recommended too. However, one trick to storing more human-readable code is to

use a single tab character for indentation. This approach uses 1/4 of the space for

indentation and can be significant when you're counting bytes.

On MacOS?

MacOS loves to generate hidden files. Luckily you can disable some of the extra

hidden files that macOS adds by running a few commands to disable search indexing

and create zero byte placeholders. Follow the steps below to maximize the amount of

space available on macOS.

Prevent & Remove MacOS Hidden Files

First find the volume name for your board. With the board plugged in run this

command in a terminal to list all the volumes:

ls -l /Volumes

Look for a volume with a name likeCIRCUITPY(the default for CircuitPython). The full

path to the volume is the/Volumes/CIRCUITPYpath.

Now follow thesteps from this question()to run these terminal commands that stop

hidden files from being created on the board:

mdutil -i off /Volumes/CIRCUITPY
cd /Volumes/CIRCUITPY
rm -rf .{,_.}{fseventsd,Spotlight-V*,Trashes}
mkdir .fseventsd
touch .fseventsd/no_log .metadata_never_index .Trashes
cd -

Replace/Volumes/CIRCUITPYin the commands above with the full path to your

board's volume if it's different. At this point all the hidden files should be cleared from

the board and some hidden files will be prevented from being created.

Alternatively, with CircuitPython 4.x and above, the special files and folders

mentioned above will be created automatically if you erase and reformat the

filesystem. WARNING: Save your files first! Do this in the REPL:

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>>> import storage
>>> storage.erase_filesystem()

However there are still some cases where hidden files will be created by MacOS. In

particular if you copy a file that was downloaded from the internet it will have special

metadata that MacOS stores as a hidden file. Luckily you can run a copy command

from the terminal to copy files without this hidden metadata file. See the steps below.

Copy Files on MacOS Without Creating Hidden Files

Once you've disabled and removed hidden files with the above commands on macOS

you need to be careful to copy files to the board with a special command that

prevents future hidden files from being created. Unfortunately you cannotuse drag

and drop copy in Finder because it will still create these hidden extended attribute

files in some cases (for files downloaded from the internet, like Adafruit's modules).

To copy a file or folder use the-Xoption for thecpcommand in a terminal. For

example to copy a file_name.mpy file to the board use a command like:

cp -X file_name.mpy /Volumes/CIRCUITPY

(Replace file_name.mpy with the name of the file you want to copy.)

Or to copy a folder and all of the files and folders contained within, use a command

like:

cp -rX folder_to_copy /Volumes/CIRCUITPY

If you are copying to the lib folder, or another folder, make sure it exists before

copying.

# if lib does not exist, you'll create a file named lib !
cp -X file_name.mpy /Volumes/CIRCUITPY/lib
# This is safer, and will complain if a lib folder does not exist.
cp -X file_name.mpy /Volumes/CIRCUITPY/lib/

Other MacOS Space-Saving Tips

If you'd like to see the amount of space used on the drive and manually delete hidden
files here's how to do so. First, move into the Volumes/ directory with cd /Volumes/ ,
and then list the amount of space used on the CIRCUITPY drive with the df

command.

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That's not very much space left! The next step is to show a list of the files currently on
the CIRCUITPY drive, including the hidden files, using the ls command. You cannot

use Finder to do this, you must do it via command line!

There are a few of the hidden files that MacOS loves to generate, all of which begin
with a ._ before the file name. Remove the ._ files using the rm command. You can
remove them all once by running rm CIRCUITPY/._* . The * acts as a wildcard to

apply the command to everything that begins with ._ at the same time.

Finally, you can run df again to see the current space used.

Nice! You have 12Ki more than before! This space can now be used for libraries and

code!

Device Locked Up or Boot Looping

In rare cases, it may happen that something in your code.py or boot.py files causes

the device to get locked up, or even go into a boot loop. A boot loop occurs when the

board reboots repeatedly and never fully loads. These are not caused by your

everyday Python exceptions, typically it's the result of a deeper problem within

CircuitPython. In this situation, it can be difficult to recover your device if CIRCUITPY

is not allowing you to modify the code.py or boot.py files. Safe mode is one recovery

option. When the device boots up in safe mode it will not run the code.py or boot.py

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scripts, but will still connect the CIRCUITPY drive so that you can remove or modify

those files as needed.

The method used to manually enter safe mode can be different for different devices.

It is also very similar to the method used for getting into bootloader mode, which is a

different thing. So it can take a few tries to get the timing right. If you end up in

bootloader mode, no problem, you can try again without needing to do anything else.

For most devices:

Press the reset button, and then when the RGB status LED blinks yellow, press the

reset button again. Since your reaction time may not be that fast, try a "slow" double

click, to catch the yellow LED on the second click.

For ESP32-S2 based devices:

Press and release the reset button, then press and release the boot button about 3/4

of a second later.

Refer to the diagrams above for boot sequence details.

Welcome to the Community!

CircuitPython is a programming language that's super simple to get started with and

great for learning. It runs on microcontrollers and works out of the box. You can plug it

in and get started with any text editor. The best part? CircuitPython comes with an

amazing, supportive community.

Everyone is welcome! CircuitPython is Open Source. This means it's available for

anyone to use, edit, copy and improve upon. This also means CircuitPython becomes

better because of you being a part of it. Whether this is your first microcontroller

board or you're a seasoned software engineer, you have something important to offer

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the Adafruit CircuitPython community. This page highlights some of the many ways

you can be a part of it!

Adafruit Discord

The Adafruit Discord server is the best place to start. Discord is where the community

comes together to volunteer and provide live support of all kinds. From general

discussion to detailed problem solving, and everything in between, Discord is a digital

maker space with makers from around the world.

There are many different channels so you can choose the one best suited to your

needs. Each channel is shown on Discord as "#channelname". There's the #help-with-

projects channel for assistance with your current project or help coming up with ideas

for your next one. There's the #show-and-tell channel for showing off your newest

creation. Don't be afraid to ask a question in any channel! If you're unsure, #general is

a great place to start. If another channel is more likely to provide you with a better

answer, someone will guide you.

The help with CircuitPython channel is where to go with your CircuitPython questions.

#help-with-circuitpython is there for new users and developers alike so feel free to

ask a question or post a comment! Everyone of any experience level is welcome to

join in on the conversation. Your contributions are important! The #circuitpython-dev

channel is available for development discussions as well.

The easiest way to contribute to the community is to assist others on Discord.

Supporting others doesn't always mean answering questions. Join in celebrating

successes! Celebrate your mistakes! Sometimes just hearing that someone else has

gone through a similar struggle can be enough to keep a maker moving forward.

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The Adafruit Discord is the 24x7x365 hackerspace that you can bring your

granddaughter to.

Visit https://adafru.it/discord ()to sign up for Discord. Everyone is looking forward to

meeting you!

CircuitPython.org

Beyond the Adafruit Learn System, which you are viewing right now, the best place to

find information about CircuitPython is circuitpython.org(). Everything you need to get

started with your new microcontroller and beyond is available. You can do things like

download CircuitPython for your microcontroller() or download the latest

CircuitPython Library bundle(), or check out which single board computers support

Blinka(). You can also get to various other CircuitPython related things like Awesome

CircuitPython or the Python for Microcontrollers newsletter. This is all incredibly

useful, but it isn't necessarily community related. So why is it included here? The Cont

ributing page().

CircuitPython itself is written in C. However, all of the Adafruit CircuitPython libraries

are written in Python. If you're interested in contributing to CircuitPython on the

Python side of things, check out circuitpython.org/contributing(). You'll find

information pertaining to every Adafruit CircuitPython library GitHub repository, giving

you the opportunity to join the community by finding a contributing option that works

for you.

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