Introduction

Classes for use in communicating with devices on a 1-Wire bus.

Dependencies

This driver depends on:

• Adafruit CircuitPython

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Usage Example

import board
from adafruit_onewire.bus import OneWireBus
ow_bus = OneWireBus(board.D2)
devices = ow_bus.scan()
for d in devices:
    print("ROM={}\tFamily=0x{:02x}".format(d.rom, d.family_code))

API Reference

OneWire Bus

Provide access to a 1-Wire bus.

• Author(s): Carter Nelson

class adafruit_onewire.bus.OneWireAddress(rom)

A class to represent a 1-Wire address.

crc

The 8 bit CRC.

family_code

The 8 bit family code.

rom

The unique 64 bit ROM code.

serial_number

The 48 bit serial number.

class adafruit_onewire.bus.OneWireBus(pin)

A class to represent a 1-Wire bus.

static crc8(data)

Perform the 1-Wire CRC check on the provided data.

Parameters:data (bytearray) – 8 byte array representing 64 bit ROM code

readinto(buf, *, start=0, end=None)

Read into buf from the device. The number of bytes read will be the length of buf.

If start or end is provided, then the buffer will be sliced as if buf[start:end]. This will not cause an allocation like buf[start:end] will so it saves memory.

Parameters:

• buf (bytearray) – buffer to write into
• start (int) – Index to start writing at
• end (int) – Index to write up to but not include

reset(required=False)

Perform a reset and check for presence pulse.

Parameters:required (bool) – require presence pulse

scan()

Scan for devices on the bus and return a list of addresses.

write(buf, *, start=0, end=None)

Write the bytes from buf to the device.

If start or end is provided, then the buffer will be sliced as if buffer[start:end]. This will not cause an allocation like buffer[start:end] will so it saves memory.

Parameters:

• buf (bytearray) – buffer containing the bytes to write
• start (int) – Index to start writing from
• end (int) – Index to read up to but not include

exception adafruit_onewire.bus.OneWireError

A class to represent a 1-Wire exception.

OneWire Device

Provides access to a single device on the 1-Wire bus.

• Author(s): Carter Nelson

class adafruit_onewire.device.OneWireDevice(bus, address)

A class to represent a single device on the 1-Wire bus.

readinto(buf, *, start=0, end=None)

Read into buf from the device. The number of bytes read will be the length of buf.

If start or end is provided, then the buffer will be sliced as if buf[start:end]. This will not cause an allocation like buf[start:end] will so it saves memory.

Parameters:

• buf (bytearray) – buffer to write into
• start (int) – Index to start writing at
• end (int) – Index to write up to but not include

write(buf, *, start=0, end=None)

Write the bytes from buf to the device.

If start or end is provided, then the buffer will be sliced as if buffer[start:end]. This will not cause an allocation like buffer[start:end] will so it saves memory.

Parameters:

• buf (bytearray) – buffer containing the bytes to write
• start (int) – Index to start writing from
• end (int) – Index to read up to but not include

Contributing

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Building locally

To build this library locally you’ll need to install the circuitpython-build-tools package.

python3 -m venv .env
source .env/bin/activate
pip install circuitpython-build-tools

Once installed, make sure you are in the virtual environment:

source .env/bin/activate

Then run the build:

circuitpython-build-bundles --filename_prefix adafruit-circuitpython-onewire --library_location .