`pwmio` – Support for PWM based protocols

The pwmio module contains classes to provide access to basic pulse IO.

All classes change hardware state and should be deinitialized when they are no longer needed if the program continues after use. To do so, either call deinit() or use a context manager. See Lifetime and ContextManagers for more info.

For example:

import time
import pwmio
import board

pwm = pwmio.PWMOut(board.LED)
pwm.duty_cycle = 2 ** 15
time.sleep(0.1)

This example will initialize the the device, set duty_cycle, and then sleep 0.1 seconds. CircuitPython will automatically turn off the PWM when it resets all hardware after program completion. Use deinit() or a with statement to do it yourself.

For the essentials of pwmio, see the CircuitPython Essentials Learn guide.

Available on these boards

01Space 0.42 OLED ESP32C3
0xCB Helios
42. Keebs Frood
8086 Commander
8086 USB Interposer
@sarfata shIRtty
AITHinker ESP32-C3S_Kit
AITHinker ESP32-C3S_Kit_2M
ARAMCON Badge 2019
ARAMCON2 Badge
ATMegaZero ESP32-S2
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 V2
Adafruit Feather ESP32-C6 4MB Flash No PSRAM
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 HUZZAH32
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 HUZZAH32 Breakout
Adafruit Hallowing M4 Express
Adafruit ItsyBitsy ESP32
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 Pixel Trinkey M0
Adafruit PyGamer
Adafruit PyPortal
Adafruit PyPortal Pynt
Adafruit PyPortal Titano
Adafruit PyRuler
Adafruit Pybadge
Adafruit QT Py ESP32 PICO
Adafruit QT Py ESP32-S3 4MB Flash 2MB PSRAM
Adafruit QT Py ESP32-S3 no psram
Adafruit QT Py ESP32C3
Adafruit QT Py ESP32S2
Adafruit QT Py M0
Adafruit QT Py M0 Haxpress
Adafruit QT Py RP2040
Adafruit QT2040 Trinkey
Adafruit Trellis M4 Express
Adafruit Trinket M0
Adafruit Vindie S2
Adafruit-Qualia-S3-RGB666
Ai Thinker ESP32-CAM
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
CRCibernetica IdeaBoard
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 Beetle ESP32-C3
DFRobot FireBeetle 2 ESP32-S3
Datanoise PicoADK
Datanoise PicoADK V2
Deneyap Kart
Deneyap Kart 1A
Deneyap Kart 1A v2
Deneyap Kart G
Deneyap Mini
Deneyap Mini v2
DynOSSAT-EDU-EPS
DynOSSAT-EDU-OBC
DynaLoRa_USB
E-Fidget
ELECFREAKS PICO:ED
ES3ink
ESP 12k NodeMCU
ESP32 Devkit V1
ESP32-C3-DevKitM-1
ESP32-C6-DevKitC-1-N8
ESP32-C6-DevKitM-1
ESP32-H2-DevKitM-1
ESP32-P4-Function-EV
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
ESP8684-DevKitC-02-N4
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 DevKitc V4 WROOM-32E
Espressif ESP32 DevKitc V4 WROVER
Espressif ESP32 TTGO T8 v1.7
Espressif ESP32-EYE
Espressif ESP32-LyraT
Espressif-ESP32-S3-LCD-EV-Board
Espressif-ESP32-S3-LCD-EV-Board_v1.5
Espruino Bangle.js 2
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
Franzininho WIFI w/Wroom
Franzininho WIFI w/Wrover
Freenove ESP32-WROVER-DEV-CAM
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
Hardkernel Odroid Go
Heltec ESP32-S3-WIFI-LoRa-V3
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 T-01C3
LILYGO TTGO T-DISPLAY v1.1
LILYGO TTGO T-DISPLAY v1.1 4M
LILYGO TTGO T-OI PLUS
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
Lilygo T-watch 2020 V3
LoC BeR M4 base board
Luatos Core-ESP32C3
M5STACK STAMP-C3
M5Stack Atom Echo
M5Stack Atom Lite
M5Stack Atom Matrix
M5Stack Atom U
M5Stack AtomS3
M5Stack AtomS3 Lite
M5Stack AtomS3U
M5Stack Cardputer
M5Stack Core Basic
M5Stack Core Fire
M5Stack Core2
M5Stack CoreS3
M5Stack Dial
M5Stack M5Paper
M5Stack Stick C
M5Stack Stick C Plus
M5Stack Timer Camera X
MDBT50Q-DB-40
MDBT50Q-RX Dongle
MEOWBIT
MORPHEANS MorphESP-240
MagiClick S3 N4R2
Maker Go ESP32C3 Supermini
Maker Go ESP32C6 Supermini
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
Metro MIMXRT1011
MicroDev microC3
MicroDev microS2
Mini SAM M4
MixGo CE
NUCLEO F446RE
NUCLEO STM32F746
NUCLEO STM32F767
NanoS3
Neuron
NodeMcu-ESP32-C2
OMGS3
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
Oxocard Artwork
Oxocard Connect
Oxocard Galaxy
Oxocard Science
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
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 Pico
Raspberry Pi Pico 2
Raspberry Pi Pico W
Robo HAT MM1 M4
S2Mini
S2Pico
SAM E54 Xplained Pro
SAM32v26
SPRESENSE
SQFMI Watchy
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 Studio XIAO ESP32C3
Seeed XIAO nRF52840 Sense
Seeed Xiao ESP32-C6 4MB Flash 512KB SRAM
Seeed Xiao ESP32-S3 Sense
Seeeduino Wio Terminal
Seeeduino XIAO
Seeeduino XIAO KB
Seeeduino XIAO RP2040
Seeeduino XIAO RP2350
Serpente
SiLabs xG24 Dev Kit
SiLabs xG24 Explorer Kit
Silicognition LLC M4-Shim
Silicognition LLC RP2040-Shim
Simmel
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
Sparkfun Thing Plus MGM240P
Spotpear ESP32C3 LCD 1.44
Sprite_v2b
StackRduino M0 PRO
Sunton ESP32-2424S012
Sunton-ESP32-8048S050
Sunton-ESP32-8048S070
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
TinyC6
TinyPICO
TinyPICO Nano
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)
VIDI X V1.1
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 ESP32S3 LCD 1.28
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 ESP32-C6 (4MB)
WeAct ESP32-C6 (8MB)
WeAct Studio Pico
WeAct Studio Pico 16MB
WeMos LOLIN32 Lite
Wemos Lolin C3 Mini
Wemos Lolin C3 Pico
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
micro:bit v2
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
sunton_esp32_2432S028
sunton_esp32_2432S032C
takayoshiotake Octave RP2040
uChip
uGame10
uGame22

class pwmio.PWMOut(pin: microcontroller.Pin, *, duty_cycle: int = 0, frequency: int = 500, variable_frequency: bool = False)

Output a Pulse Width Modulated signal on a given pin.

Note

The exact frequencies possible depend on the specific microcontroller. If the requested frequency is within the available range, one of the two nearest possible frequencies to the requested one is selected.

If the requested frequency is outside the range, either (A) a ValueError may be raised or (B) the highest or lowest frequency is selected. This behavior is microcontroller-dependent, and may depend on whether it’s the upper or lower bound that is exceeded.

In any case, the actual frequency (rounded to 1Hz) is available in the frequency property after construction.

Note

The frequency is calculated based on a nominal CPU frequency. However, depending on the board, the error between the nominal and actual CPU frequency can be large (several hundred PPM in the case of crystal oscillators and up to ten percent in the case of RC oscillators)

Create a PWM object associated with the given pin. This allows you to write PWM signals out on the given pin. Frequency is fixed after init unless variable_frequency is True.

Note

When variable_frequency is True, further PWM outputs may be limited because it may take more internal resources to be flexible. So, when outputting both fixed and flexible frequency signals construct the fixed outputs first.

Parameters:

pin (Pin) – The pin to output to
duty_cycle (int) – The fraction of each pulse which is high. 16-bit
frequency (int) – The target frequency in Hertz (32-bit)
variable_frequency (bool) – True if the frequency will change over time

Simple LED on:

import pwmio
import board

pwm = pwmio.PWMOut(board.LED)

while True:
    pwm.duty_cycle = 2 ** 15  # Cycles the pin with 50% duty cycle (half of 2 ** 16) at the default 500hz

PWM LED fade:

import pwmio
import board

pwm = pwmio.PWMOut(board.LED)  # output on LED pin with default of 500Hz

while True:
    for cycle in range(0, 65535):  # Cycles through the full PWM range from 0 to 65535
        pwm.duty_cycle = cycle  # Cycles the LED pin duty cycle through the range of values
    for cycle in range(65534, 0, -1):  # Cycles through the PWM range backwards from 65534 to 0
        pwm.duty_cycle = cycle  # Cycles the LED pin duty cycle through the range of values

PWM at specific frequency (servos and motors):

import pwmio
import board

pwm = pwmio.PWMOut(board.D13, frequency=50)
pwm.duty_cycle = 2 ** 15  # Cycles the pin with 50% duty cycle (half of 2 ** 16) at 50hz

Variable frequency (usually tones):

import pwmio
import board
import time

pwm = pwmio.PWMOut(board.D13, duty_cycle=2 ** 15, frequency=440, variable_frequency=True)
time.sleep(0.2)
pwm.frequency = 880
time.sleep(0.1)

deinit() → None: Deinitialises the PWMOut and releases any hardware resources for reuse.

__enter__() → PWMOut: No-op used by Context Managers.

__exit__() → None: Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.

duty_cycle: int

16 bit value that dictates how much of one cycle is high (1) versus low (0). 0xffff will always be high, 0 will always be low and 0x7fff will be half high and then half low.

Depending on how PWM is implemented on a specific board, the internal representation for duty cycle might have less than 16 bits of resolution. Reading this property will return the value from the internal representation, so it may differ from the value set.

frequency: int

32 bit value that dictates the PWM frequency in Hertz (cycles per second). Only writeable when constructed with variable_frequency=True.

Depending on how PWM is implemented on a specific board, the internal value for the PWM’s duty cycle may need to be recalculated when the frequency changes. In these cases, the duty cycle is automatically recalculated from the original duty cycle value. This should happen without any need to manually re-set the duty cycle. However, an output glitch may occur during the adjustment.

pwmio – Support for PWM based protocols

`pwmio` – Support for PWM based protocols