busio – Hardware accelerated external bus access
The busio module contains classes to support a variety of serial
protocols.
When the microcontroller does not support the behavior in a hardware
accelerated fashion it may internally use a bitbang routine. However, if
hardware support is available on a subset of pins but not those provided,
then a RuntimeError will be raised. Use the bitbangio module to explicitly
bitbang a serial protocol on any general purpose pins.
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 busio
from board import *
i2c = busio.I2C(SCL, SDA)
i2c.try_lock()
print(i2c.scan())
i2c.unlock()
i2c.deinit()
This example will initialize the the device, lock the I2C bus, run
scan(), unlock the bus,
and then deinit() the hardware.
The last step is optional because CircuitPython automatically
resets hardware after a program finishes.
Note that drivers will typically handle communication if provided the bus
instance (such as busio.I2C(board.SCL, board.SDA)), and that many of
the methods listed here are lower level functionalities that are needed
for working with custom drivers.
Tutorial for I2C and SPI: https://learn.adafruit.com/circuitpython-basics-i2c-and-spi
Tutorial for UART: https://learn.adafruit.com/circuitpython-essentials/circuitpython-uart-serial
Available on these boards
- class busio.I2C(scl: microcontroller.Pin, sda: microcontroller.Pin, *, frequency: int = 100000, timeout: int = 255)
Two wire serial protocol
I2C is a two-wire protocol for communicating between devices. At the physical level it consists of 2 wires: SCL and SDA, the clock and data lines respectively.
See also
Using this class directly requires careful lock management. Instead, use
I2CDeviceto manage locks.See also
Using this class to directly read registers requires manual bit unpacking. Instead, use an existing driver or make one with Register data descriptors.
- Parameters:
- __exit__() None
Automatically deinitializes the hardware on context exit. See Lifetime and ContextManagers for more info.
- scan() List[int]
Scan all I2C addresses between 0x08 and 0x77 inclusive and return a list of those that respond.
- Returns:
List of device ids on the I2C bus
- Return type:
- try_lock() bool
Attempts to grab the I2C lock. Returns True on success.
- Returns:
True when lock has been grabbed
- Return type:
- readfrom_into(address: int, buffer: circuitpython_typing.WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) None
Read into
bufferfrom the device selected byaddress. At least one byte must be read.If
startorendis provided, then the buffer will be sliced as ifbuffer[start:end]were passed, but without copying the data. The number of bytes read will be the length ofbuffer[start:end].
- writeto(address: int, buffer: circuitpython_typing.ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) None
Write the bytes from
bufferto the device selected byaddressand then transmit a stop bit.If
startorendis provided, then the buffer will be sliced as ifbuffer[start:end]were passed, but without copying the data. The number of bytes written will be the length ofbuffer[start:end].Writing a buffer or slice of length zero is permitted, as it can be used to poll for the existence of a device.
- writeto_then_readfrom(address: int, out_buffer: circuitpython_typing.ReadableBuffer, in_buffer: circuitpython_typing.WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) None
Write the bytes from
out_bufferto the device selected byaddress, generate no stop bit, generate a repeated start and read intoin_buffer.out_bufferandin_buffercan be the same buffer because they are used sequentially.If
out_startorout_endis provided, then the buffer will be sliced as ifout_buffer[out_start:out_end]were passed, but without copying the data. The number of bytes written will be the length ofout_buffer[start:end].If
in_startorin_endis provided, then the input buffer will be sliced as ifin_buffer[in_start:in_end]were passed, The number of bytes read will be the length ofout_buffer[in_start:in_end].- Parameters:
address (int) – 7-bit device address
out_buffer (ReadableBuffer) – buffer containing the bytes to write
in_buffer (WriteableBuffer) – buffer to write into
out_start (int) – beginning of
out_buffersliceout_end (int) – end of
out_bufferslice; if not specified, uselen(out_buffer)in_start (int) – beginning of
in_bufferslicein_end (int) – end of
in_buffer slice; if not specified, uselen(in_buffer)
- class busio.SPI(clock: microcontroller.Pin, MOSI: microcontroller.Pin | None = None, MISO: microcontroller.Pin | None = None, half_duplex: bool = False)
A 3-4 wire serial protocol
SPI is a serial protocol that has exclusive pins for data in and out of the main device. It is typically faster than
I2Cbecause a separate pin is used to select a device rather than a transmitted address. This class only manages three of the four SPI lines:clock,MOSI,MISO. Its up to the client to manage the appropriate select line, often abbreviatedCSorSS. (This is common because multiple secondaries can share theclock,MOSIandMISOlines and therefore the hardware.)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
- Diodes Delight Piunora
- 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
- Meow Meow
- Metro MIMXRT1011
- MicroDev microC3
- MicroDev microS2
- Mini SAM M4
- MixGo CE
- NUCLEO F446RE
- NUCLEO STM32F746
- NUCLEO STM32F767
- NUCLEO STM32H743
- NanoS3
- Neuron
- NodeMcu-ESP32-C2
- 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
- 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
- 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
- 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 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
Construct an SPI object on the given pins.
Note
The SPI peripherals allocated in order of desirability, if possible, such as highest speed and not shared use first. For instance, on the nRF52840, there is a single 32MHz SPI peripheral, and multiple 8MHz peripherals, some of which may also be used for I2C. The 32MHz SPI peripheral is returned first, then the exclusive 8MHz SPI peripheral, and finally the shared 8MHz peripherals.
See also
Using this class directly requires careful lock management. Instead, use
SPIDeviceto manage locks.See also
Using this class to directly read registers requires manual bit unpacking. Instead, use an existing driver or make one with Register data descriptors.
- Parameters:
Limitations:
half_duplexis available only on STM; other chips do not have the hardware support.- __exit__() None
Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.
- configure(*, baudrate: int = 100000, polarity: int = 0, phase: int = 0, bits: int = 8) None
Configures the SPI bus. The SPI object must be locked.
- Parameters:
baudrate (int) – the desired clock rate in Hertz. The actual clock rate may be higher or lower due to the granularity of available clock settings. Check the
frequencyattribute for the actual clock rate.polarity (int) – the base state of the clock line (0 or 1)
phase (int) – the edge of the clock that data is captured. First (0) or second (1). Rising or falling depends on clock polarity.
bits (int) – the number of bits per word
Note
On the SAMD21, it is possible to set the baudrate to 24 MHz, but that speed is not guaranteed to work. 12 MHz is the next available lower speed, and is within spec for the SAMD21.
Note
On the nRF52840, these baudrates are available: 125kHz, 250kHz, 1MHz, 2MHz, 4MHz, and 8MHz. If you pick a a baudrate other than one of these, the nearest lower baudrate will be chosen, with a minimum of 125kHz. Two SPI objects may be created, except on the Circuit Playground Bluefruit, which allows only one (to allow for an additional I2C object).
- try_lock() bool
Attempts to grab the SPI lock. Returns True on success.
- Returns:
True when lock has been grabbed
- Return type:
- write(buffer: circuitpython_typing.ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) None
Write the data contained in
buffer. The SPI object must be locked. If the buffer is empty, nothing happens.If
startorendis provided, then the buffer will be sliced as ifbuffer[start:end]were passed, but without copying the data. The number of bytes written will be the length ofbuffer[start:end].
- readinto(buffer: circuitpython_typing.WriteableBuffer, *, start: int = 0, end: int = sys.maxsize, write_value: int = 0) None
Read into
bufferwhile writingwrite_valuefor each byte read. The SPI object must be locked. If the number of bytes to read is 0, nothing happens.If
startorendis provided, then the buffer will be sliced as ifbuffer[start:end]were passed. The number of bytes read will be the length ofbuffer[start:end].- Parameters:
buffer (WriteableBuffer) – read bytes into this buffer
start (int) – beginning of buffer slice
end (int) – end of buffer slice; if not specified, it will be the equivalent value of
len(buffer)and for any value provided it will take the value ofmin(end, len(buffer))write_value (int) – value to write while reading
- write_readinto(out_buffer: circuitpython_typing.ReadableBuffer, in_buffer: circuitpython_typing.WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) None
Write out the data in
out_bufferwhile simultaneously reading data intoin_buffer. The SPI object must be locked.If
out_startorout_endis provided, then the buffer will be sliced as ifout_buffer[out_start:out_end]were passed, but without copying the data. The number of bytes written will be the length ofout_buffer[out_start:out_end].If
in_startorin_endis provided, then the input buffer will be sliced as ifin_buffer[in_start:in_end]were passed, The number of bytes read will be the length ofout_buffer[in_start:in_end].The lengths of the slices defined by
out_buffer[out_start:out_end]andin_buffer[in_start:in_end]must be equal. If buffer slice lengths are both 0, nothing happens.- Parameters:
out_buffer (ReadableBuffer) – write out bytes from this buffer
in_buffer (WriteableBuffer) – read bytes into this buffer
out_start (int) – beginning of
out_buffersliceout_end (int) – end of
out_bufferslice; if not specified, uselen(out_buffer)in_start (int) – beginning of
in_bufferslicein_end (int) – end of
in_buffer slice; if not specified, uselen(in_buffer)
- class busio.UART(tx: microcontroller.Pin | None = None, rx: microcontroller.Pin | None = None, *, rts: microcontroller.Pin | None = None, cts: microcontroller.Pin | None = None, rs485_dir: microcontroller.Pin | None = None, rs485_invert: bool = False, baudrate: int = 9600, bits: int = 8, parity: Parity | None = None, stop: int = 1, timeout: float = 1, receiver_buffer_size: int = 64)
A bidirectional serial protocol
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 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 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
- Diodes Delight Piunora
- 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
- Meow Meow
- Metro MIMXRT1011
- MicroDev microC3
- MicroDev microS2
- Mini SAM M4
- MixGo CE
- NUCLEO F446RE
- NUCLEO STM32F746
- NUCLEO STM32F767
- NUCLEO STM32H743
- NanoS3
- Neuron
- NodeMcu-ESP32-C2
- 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
- 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
- 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
- Renode Cortex-M0+
- 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 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
A common bidirectional serial protocol that uses an an agreed upon speed rather than a shared clock line.
- Parameters:
tx (Pin) – the pin to transmit with, or
Noneif thisUARTis receive-only.rx (Pin) – the pin to receive on, or
Noneif thisUARTis transmit-only.rts (Pin) – the pin for rts, or
Noneif rts not in use.cts (Pin) – the pin for cts, or
Noneif cts not in use.rs485_dir (Pin) – the output pin for rs485 direction setting, or
Noneif rs485 not in use.rs485_invert (bool) – rs485_dir pin active high when set. Active low otherwise.
baudrate (int) – the transmit and receive speed.
bits (int) – the number of bits per byte, 5 to 9.
parity (Parity) – the parity used for error checking.
stop (int) – the number of stop bits, 1 or 2.
timeout (float) – the timeout in seconds to wait for the first character and between subsequent characters when reading. Raises
ValueErrorif timeout >100 seconds.receiver_buffer_size (int) – the character length of the read buffer (0 to disable). (When a character is 9 bits the buffer will be 2 * receiver_buffer_size bytes.)
txandrxcannot both beNone.New in CircuitPython 4.0:
timeouthas incompatibly changed units from milliseconds to seconds. The new upper limit ontimeoutis meant to catch mistaken use of milliseconds.Limitations: RS485 is not supported on SAMD, Nordic, Broadcom, Spresense, or STM. On i.MX and Raspberry Pi RP2040, RS485 support is implemented in software: The timing for the
rs485_dirpin signal is done on a best-effort basis, and may not meet RS485 specifications intermittently.- __exit__() None
Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.
- read(nbytes: int | None = None) bytes | None
Read bytes. If
nbytesis specified then read at most that many bytes. Otherwise, read everything that arrives until the connection times out. Providing the number of bytes expected is highly recommended because it will be faster. If no bytes are read, returnNone.Note
When no bytes are read due to a timeout, this function returns
None. This matches the behavior ofio.RawIOBase.readin Python 3, but differs from pyserial which returnsb''in that situation.- Returns:
Data read
- Return type:
bytes or None
- readinto(buf: circuitpython_typing.WriteableBuffer) int | None
Read bytes into the
buf. Read at mostlen(buf)bytes.- Returns:
number of bytes read and stored into
buf- Return type:
int or None (on a non-blocking error)
New in CircuitPython 4.0: No length parameter is permitted.
- readline() bytes
Read a line, ending in a newline character, or return
Noneif a timeout occurs sooner, or return everything readable if no newline is found andtimeout=0- Returns:
the line read
- Return type:
bytes or None
- write(buf: circuitpython_typing.ReadableBuffer) int | None
Write the buffer of bytes to the bus.
New in CircuitPython 4.0:
bufmust be bytes, not a string.- return:
the number of bytes written
- rtype:
int or None