usb_cdc
– USB CDC Serial streams
The usb_cdc
module allows access to USB CDC (serial) communications.
On Windows, each Serial
is visible as a separate COM port. The ports will often
be assigned consecutively, console
first, but this is not always true.
On Linux, the ports are typically /dev/ttyACM0
and /dev/ttyACM1
.
The console
port will usually be first.
On MacOS, the ports are typically /dev/cu.usbmodem<something>
. The something
varies based on the USB bus and port used. The console
port will usually be first.
Available on these boards
- 0xCB Helios
- 42. Keebs Frood
- 8086 Commander
- 8086 USB Interposer
- @sarfata shIRtty
- ARAMCON Badge 2019
- ARAMCON2 Badge
- ATMegaZero ESP32-S2
- Adafruit BLM Badge
- Adafruit CLUE nRF52840 Express
- Adafruit Camera
- Adafruit Circuit Playground Bluefruit
- Adafruit Circuit Playground Express 4-H
- Adafruit CircuitPlayground Express
- Adafruit CircuitPlayground Express with Crickit libraries
- Adafruit CircuitPlayground Express with displayio
- Adafruit EdgeBadge
- Adafruit Feather Bluefruit Sense
- Adafruit Feather ESP32-S2 Reverse TFT
- Adafruit Feather ESP32-S2 TFT
- Adafruit Feather ESP32-S3 Reverse TFT
- Adafruit Feather ESP32-S3 TFT
- Adafruit Feather ESP32S2
- Adafruit Feather ESP32S3 4MB Flash 2MB PSRAM
- Adafruit Feather ESP32S3 No PSRAM
- Adafruit Feather M0 Adalogger
- Adafruit Feather M0 Basic
- Adafruit Feather M0 Express
- Adafruit Feather M0 Express with Crickit libraries
- Adafruit Feather M0 RFM69
- Adafruit Feather M0 RFM9x
- Adafruit Feather M4 CAN
- Adafruit Feather M4 Express
- Adafruit Feather MIMXRT1011
- Adafruit Feather RP2040
- Adafruit Feather RP2040 Adalogger
- Adafruit Feather RP2040 CAN
- Adafruit Feather RP2040 DVI
- Adafruit Feather RP2040 Prop-Maker
- Adafruit Feather RP2040 RFM
- Adafruit Feather RP2040 Scorpio
- Adafruit Feather RP2040 ThinkInk
- Adafruit Feather RP2040 USB Host
- Adafruit Feather RP2350
- Adafruit Feather STM32F405 Express
- Adafruit Feather nRF52840 Express
- Adafruit Floppsy RP2040
- Adafruit FunHouse
- Adafruit Gemma M0
- Adafruit Gemma M0 PyCon 2018
- Adafruit Grand Central M4 Express
- Adafruit Hallowing M4 Express
- Adafruit ItsyBitsy M0 Express
- Adafruit ItsyBitsy M4 Express
- Adafruit ItsyBitsy RP2040
- Adafruit ItsyBitsy nRF52840 Express
- Adafruit KB2040
- Adafruit LED Glasses Driver nRF52840
- Adafruit Macropad RP2040
- Adafruit MagTag
- Adafruit Matrix Portal M4
- Adafruit MatrixPortal S3
- Adafruit Metro ESP32S2
- Adafruit Metro ESP32S3
- Adafruit Metro M0 Express
- Adafruit Metro M4 Airlift Lite
- Adafruit Metro M4 Express
- Adafruit Metro RP2040
- Adafruit Metro RP2350
- Adafruit Metro nRF52840 Express
- Adafruit Monster M4SK
- Adafruit NeoKey Trinkey M0
- Adafruit NeoPixel Trinkey M0
- Adafruit Pixel Trinkey M0
- Adafruit ProxLight Trinkey M0
- Adafruit PyGamer
- Adafruit PyPortal
- Adafruit PyPortal Pynt
- Adafruit PyPortal Titano
- Adafruit PyRuler
- Adafruit Pybadge
- Adafruit QT Py ESP32-S3 4MB Flash 2MB PSRAM
- Adafruit QT Py ESP32-S3 no psram
- Adafruit QT Py ESP32S2
- Adafruit QT Py M0
- Adafruit QT Py M0 Haxpress
- Adafruit QT Py RP2040
- Adafruit QT2040 Trinkey
- Adafruit Rotary Trinkey M0
- Adafruit SHT4x Trinkey M0
- Adafruit Slide Trinkey M0
- Adafruit TRRS Trinkey M0
- Adafruit Trellis M4 Express
- Adafruit Trinket M0
- Adafruit Vindie S2
- Adafruit-Qualia-S3-RGB666
- AloriumTech Evo M51
- Archi RP2040
- Arduino MKR Zero
- Arduino MKR1300
- Arduino Nano 33 BLE
- Arduino Nano 33 BLE Rev2
- Arduino Nano 33 IoT
- Arduino Nano ESP32
- Arduino Nano RP2040 Connect
- Arduino Zero
- Artisense Reference Design RD00
- AtelierDuMaker nRF52840 Breakout
- AutosportLabs-ESP32-CAN-X2
- BARDUINO 4.0.2
- BBQ20KBD
- BDMICRO VINA-D51
- BLE-SS dev board Multi Sensor
- BLING!
- BLOK
- BPI-Bit-S2
- BPI-Leaf-S3
- BPI-PicoW-S3
- BastBLE
- BastWiFi
- Bee-Data-Logger
- Bee-Motion-S3
- Bee-S3
- BlizzardS3
- BlueMicro833
- BlueMicro840
- Bradán Lane STUDIO Explorer Badge
- COSMO-Pico
- CP Sapling M0
- CP Sapling M0 w/ SPI Flash
- CP32-M4
- Capable Robot Programmable USB Hub
- Cedar Grove StringCar M0 Express
- Challenger NB RP2040 WiFi
- Challenger RP2040 LTE
- Challenger RP2040 LoRa
- Challenger RP2040 SD/RTC
- Challenger RP2040 SubGHz
- Challenger RP2040 WiFi
- Challenger RP2040 WiFi/BLE
- Challenger+ RP2350 BConnect
- Challenger+ RP2350 WiFi6/BLE5
- Circuit Playground Express Digi-Key PyCon 2019
- CircuitART Zero S3
- CircuitBrains Basic
- CircuitBrains Deluxe
- ColumbiaDSL-Sensor-Board-V1
- CrumpS2
- Cytron EDU PICO W
- Cytron IRIV IO Controller
- Cytron MOTION 2350 Pro
- Cytron Maker Feather AIoT S3
- Cytron Maker Nano RP2040
- Cytron Maker Pi RP2040
- Cytron Maker Uno RP2040
- DFRobot FireBeetle 2 ESP32-S3
- Datanoise PicoADK
- Datanoise PicoADK V2
- Deneyap Kart 1A v2
- Deneyap Mini
- Deneyap Mini v2
- Diodes Delight Piunora
- DynOSSAT-EDU-EPS
- DynOSSAT-EDU-OBC
- DynaLoRa_USB
- E-Fidget
- ELECFREAKS PICO:ED
- ES3ink
- ESP 12k NodeMCU
- ESP32-S2-DevKitC-1-N4
- ESP32-S2-DevKitC-1-N4R2
- ESP32-S2-DevKitC-1-N8R2
- ESP32-S3-Box-2.5
- ESP32-S3-Box-Lite
- ESP32-S3-DevKitC-1-N16
- ESP32-S3-DevKitC-1-N32R8
- ESP32-S3-DevKitC-1-N8
- ESP32-S3-DevKitC-1-N8R2
- ESP32-S3-DevKitC-1-N8R8
- ESP32-S3-DevKitC-1-N8R8-with-HACKTABLET
- ESP32-S3-DevKitM-1-N8
- ESP32-S3-EYE
- ESP32-S3-USB-OTG-N8
- Electrolama minik
- Electronic Cats Bast Pro Mini M0
- Electronic Cats CatWAN USBStick
- Electronic Cats Hunter Cat NFC
- Electronic Cats NFC Copy Cat
- Electronut Labs Blip
- Electronut Labs Papyr
- EncoderPad RP2040
- Escornabot Makech
- Espressif-ESP32-S3-LCD-EV-Board
- Espressif-ESP32-S3-LCD-EV-Board_v1.5
- Espruino Pico
- Espruino Wifi
- Feather MIMXRT1011
- Feather MIMXRT1062
- FeatherS2
- FeatherS2 Neo
- FeatherS2 PreRelease
- FeatherS3
- FeatherS3 Neo
- Fig Pi
- Flipper Zero Wi-Fi Dev
- Fluff M0
- Fomu
- Franzininho WIFI w/Wroom
- Franzininho WIFI w/Wrover
- Gravitech Cucumber M
- Gravitech Cucumber MS
- Gravitech Cucumber R
- Gravitech Cucumber RS
- HEIA-FR Picomo V2
- HMI-DevKit-1.1
- Hack Club Sprig
- Hacked Feather M0 Express with 8Mbyte SPI flash
- HalloWing M0 Express
- HexKyS2
- HiiBot BlueFi
- IMXRT1010-EVK
- IMXRT1015-EVK
- IkigaiSense Vita nRF52840
- IoTs2
- J&J Studios datum-Distance
- J&J Studios datum-IMU
- J&J Studios datum-Light
- J&J Studios datum-Weather
- Kaluga 1
- LILYGO T-DECK
- LILYGO T-DISPLAY
- LILYGO T-DISPLAY S3 v1.2
- LILYGO T-Display S3 Pro
- LILYGO T-Watch-S3
- LILYGO TEMBED ESP32S3
- LILYGO TTGO T8 ESP32-S2
- LILYGO TTGO T8 ESP32-S2 w/Display
- LOLIN S3 16MB Flash 8MB PSRAM
- LOLIN S3 MINI 4MB Flash 2MB PSRAM
- LOLIN S3 PRO 16MB Flash 8MB PSRAM
- LoC BeR M4 base board
- M5Stack AtomS3
- M5Stack AtomS3 Lite
- M5Stack AtomS3U
- M5Stack Cardputer
- M5Stack CoreS3
- M5Stack Dial
- MDBT50Q-DB-40
- MDBT50Q-RX Dongle
- MEOWBIT
- MORPHEANS MorphESP-240
- MagiClick S3 N4R2
- Maker badge by Czech maker
- MakerDiary nRF52840 MDK
- MakerDiary nRF52840 MDK USB Dongle
- MakerFabs-ESP32-S3-Parallel-TFT-With-Touch-7inch
- Makerdiary M60 Keyboard
- Makerdiary Pitaya Go
- Makerdiary nRF52840 Connect Kit
- Makerdiary nRF52840 M.2 Developer Kit
- Maple Computing Elite-Pi
- Melopero Shake RP2040
- Meow Meow
- Metro MIMXRT1011
- MicroDev microS2
- Mini SAM M4
- MixGo CE
- NUCLEO F446RE
- NUCLEO STM32F746
- NUCLEO STM32F767
- NUCLEO STM32H743
- NanoS3
- Neuron
- OMGS3
- OPENMV-H7 R1
- Oak Dev Tech BREAD2040
- Oak Dev Tech Cast-Away RP2040
- Oak Dev Tech PixelWing ESP32S2
- Oak Dev Tech RPGA Feather
- Open Hardware Summit 2020 Badge
- P1AM-200
- PCA10056 nRF52840-DK
- PCA10059 nRF52840 Dongle
- PCA10100 nRF52833 DK
- PYB LR Nano V2
- Pajenicko PicoPad
- Particle Argon
- Particle Boron
- Particle Xenon
- PewPew 10.2
- PewPew LCD
- PewPew M4
- PicoPlanet
- PillBug
- Pimoroni Badger 2040
- Pimoroni Badger 2040 W
- Pimoroni Inky Frame 5.7
- Pimoroni Inky Frame 7.3
- Pimoroni Interstate 75
- Pimoroni Keybow 2040
- Pimoroni Motor 2040
- Pimoroni PGA2040
- Pimoroni PGA2350
- Pimoroni Pico DV Base W
- Pimoroni Pico LiPo (16MB)
- Pimoroni Pico LiPo (4MB)
- Pimoroni Pico Plus 2
- Pimoroni Pico dv Base
- Pimoroni PicoSystem
- Pimoroni Plasma 2040
- Pimoroni Plasma 2040W
- Pimoroni Plasma 2350
- Pimoroni Servo 2040
- Pimoroni Tiny 2040 (2MB)
- Pimoroni Tiny 2040 (8MB)
- Pimoroni Tiny 2350
- Pimoroni Tiny FX
- ProS3
- PyCubedv04
- PyCubedv04-MRAM
- PyCubedv05
- PyCubedv05-MRAM
- PyKey 18 Numpad
- PyKey 44 Ergo
- PyKey 60
- PyKey 87 TKL
- PyboardV1_1
- RF.Guru RP2040
- RGBTouch Mini
- RP2.65-F
- RP2040 Stamp
- RP2350 Stamp
- RP2350 Stamp XL
- Raspberry Breadstick
- Raspberry Pi 4B
- Raspberry Pi Compute Module 4
- Raspberry Pi Compute Module 4 IO Board
- Raspberry Pi Pico
- Raspberry Pi Pico 2
- Raspberry Pi Pico W
- Raspberry Pi Zero
- Raspberry Pi Zero 2W
- Raspberry Pi Zero W
- Robo HAT MM1 M4
- S2Mini
- S2Pico
- SAM E54 Xplained Pro
- SAM32v26
- SPRESENSE
- SSCI ISP1807 Dev Board
- SSCI ISP1807 Micro Board
- ST STM32F746G Discovery
- STM32F411E_DISCO
- STM32F412G_DISCO
- STM32F4_DISCO
- Saola 1 w/Wroom
- Saola 1 w/Wrover
- Seeed XIAO nRF52840 Sense
- Seeed Xiao ESP32-S3 Sense
- Seeeduino Wio Terminal
- Seeeduino XIAO
- Seeeduino XIAO KB
- Seeeduino XIAO RP2040
- Seeeduino XIAO RP2350
- Serpente
- Silicognition LLC M4-Shim
- Silicognition LLC RP2040-Shim
- SparkFun LUMIDrive
- SparkFun MicroMod RP2040 Processor
- SparkFun MicroMod SAMD51 Processor
- SparkFun MicroMod nRF52840 Processor
- SparkFun Pro Micro RP2040
- SparkFun Pro Micro RP2350
- SparkFun Pro nRF52840 Mini
- SparkFun Qwiic Micro
- SparkFun RedBoard Turbo
- SparkFun SAMD21 Dev Breakout
- SparkFun SAMD21 Mini Breakout
- SparkFun STM32 MicroMod Processor
- SparkFun Teensy MicroMod Processor
- SparkFun Thing Plus - RP2040
- SparkFun Thing Plus - SAMD51
- SparkFun Thing Plus - STM32
- Sprite_v2b
- StackRduino M0 PRO
- SuperMini NRF52840
- Swan R5
- TG-Boards' Datalore IP M4
- TG-Watch
- THUNDERPACK_v11
- THUNDERPACK_v12
- TTGO T8 ESP32-S2-WROOM
- Targett Module Clip w/Wroom
- Targett Module Clip w/Wrover
- Teensy 4.0
- Teensy 4.1
- Teknikio Bluebird
- The Open Book Feather
- ThingPulse Pendrive S3
- TinkeringTech ScoutMakes Azul
- TinyS2
- TinyS3
- TinyWATCH S3
- Trinket M0 Haxpress
- UARTLogger II
- VCC-GND Studio YD RP2040
- VCC-GND YD-ESP32-S3 (N16R8)
- VCC-GND YD-ESP32-S3 (N8R8)
- W5100S-EVB-Pico
- W5500-EVB-Pico
- WK-50 Trackball Keyboard
- WSC-1450
- WarmBit BluePixel nRF52840
- Waveshare ESP32-S2-Pico
- Waveshare ESP32-S2-Pico-LCD
- Waveshare ESP32-S3-GEEK
- Waveshare ESP32-S3-Pico
- Waveshare ESP32-S3-Tiny
- Waveshare ESP32-S3-Zero
- Waveshare RP2040-GEEK
- Waveshare RP2040-LCD-0.96
- Waveshare RP2040-LCD-1.28
- Waveshare RP2040-One
- Waveshare RP2040-PiZero
- Waveshare RP2040-Plus (16MB)
- Waveshare RP2040-Plus (4MB)
- Waveshare RP2040-TOUCH-LCD-1.28
- Waveshare RP2040-Tiny
- Waveshare RP2040-Zero
- WeAct Studio Pico
- WeAct Studio Pico 16MB
- Winterbloom Big Honking Button
- Winterbloom Sol
- WisdPi Ardu2040M
- WisdPi Tiny RP2040
- XinaBox CC03
- XinaBox CS11
- iLabs Challenger 840
- iMX RT 1020 EVK
- iMX RT 1040 EVK
- iMX RT 1050 EVKB
- iMX RT 1060 EVK
- iMX RT 1060 EVKB
- iMX RT1011 Nano Kit
- keithp.com snekboard
- nanoESP32-S2 w/Wrover
- nanoESP32-S2 w/Wroom
- ndGarage[n°] Bit6: FeatherSnow-v2
- ndGarage[n°]Bit6:FeatherSnow
- nice!nano
- nullbits Bit-C PRO
- senseBox MCU
- senseBox MCU-S2 ESP32S2
- splitkb.com Liatris
- stm32f411ce-blackpill
- stm32f411ce-blackpill-with-flash
- takayoshiotake Octave RP2040
- uChip
- uGame10
- uGame22
-
usb_cdc.console: Serial | None
- The
console
Serial
object is used for the REPL, and for sys.stdin
and sys.stdout
. console
is None
if disabled.
However, note that sys.stdin
and sys.stdout
are text-based streams,
and the console
object is a binary stream.
You do not normally need to write to console
unless you want to write binary data.
-
usb_cdc.data: Serial | None
A Serial
object that can be used to send and receive binary data to and from
the host.
Note that data
is disabled by default. data
is None
if disabled.
-
usb_cdc.disable() → None
Do not present any USB CDC device to the host.
Can be called in boot.py
, before USB is connected.
Equivalent to usb_cdc.enable(console=False, data=False)
.
-
usb_cdc.enable(*, console: bool = True, data: bool = False) → None
Enable or disable each CDC device. Can be called in boot.py
, before USB is connected.
- Parameters:
bool (data) – Enable or disable the console
USB serial device.
True to enable; False to disable. Enabled by default.
bool – Enable or disable the data
USB serial device.
True to enable; False to disable. Disabled by default.
If you enable too many devices at once, you will run out of USB endpoints.
The number of available endpoints varies by microcontroller.
CircuitPython will go into safe mode after running boot.py to inform you if
not enough endpoints are available.
-
class usb_cdc.Serial
Receives cdc commands over USB
You cannot create an instance of usb_cdc.Serial
.
The available instances are in the usb_cdc.serials
tuple.
-
read(size: int = 1) → bytes
Read at most size
bytes. If size
exceeds the internal buffer size
only the bytes in the buffer will be read. If timeout
is > 0 or None
,
and fewer than size
bytes are available, keep waiting until the timeout
expires or size
bytes are available.
- Returns:
Data read
- Return type:
bytes
-
readinto(buf: circuitpython_typing.WriteableBuffer) → int
Read bytes into the buf
. Read at most len(buf)
bytes. If timeout
is > 0 or None
, keep waiting until the timeout expires or len(buf)
bytes are available.
- Returns:
number of bytes read and stored into buf
- Return type:
int
-
readline(size: int = -1) → bytes | None
Read a line ending in a newline character (”\n”), including the newline.
Return everything readable if no newline is found and timeout
is 0.
Return None
in case of error.
This is a binary stream: the newline character “\n” cannot be changed.
If the host computer transmits “\r” it will also be included as part of the line.
- Parameters:
size (int) – maximum number of characters to read. -1
means as many as possible.
- Returns:
the line read
- Return type:
bytes or None
-
readlines() → List[bytes | None]
Read multiple lines as a list, using readline()
.
Warning
If timeout
is None
,
readlines()
will never return, because there is no way to indicate end of stream.
- Returns:
a list of the line read
- Return type:
list
-
write(buf: circuitpython_typing.ReadableBuffer) → int
Write as many bytes as possible from the buffer of bytes.
- Returns:
the number of bytes written
- Return type:
int
-
flush() → None
Force out any unwritten bytes, waiting until they are written.
-
connected: bool
True if this Serial is connected to a host. (read-only)
Note
The host is considered to be connected if it is asserting DTR (Data Terminal Ready).
Most terminal programs and pyserial
assert DTR when opening a serial connection.
However, the C# SerialPort
API does not. You must set SerialPort.DtrEnable
.
-
in_waiting: int
Returns the number of bytes waiting to be read on the USB serial input. (read-only)
-
out_waiting: int
Returns the number of bytes waiting to be written on the USB serial output. (read-only)
-
reset_input_buffer() → None
Clears any unread bytes.
-
reset_output_buffer() → None
Clears any unwritten bytes.
-
timeout: float | None
The initial value of timeout
is None
. If None
, wait indefinitely to satisfy
the conditions of a read operation. If 0, do not wait. If > 0, wait only timeout
seconds.
-
write_timeout: float | None
The initial value of write_timeout
is None
. If None
, wait indefinitely to finish
writing all the bytes passed to write()
.If 0, do not wait.
If > 0, wait only write_timeout
seconds.