Knowledge Base

The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.

1 Wire Pi

Created 11/05/2016 | 1 Wire Pi expansion board legacy information

This item has been replaced with the 1 Wire Pi Plus.

https://www.abelectronics.co.uk/p/60/1-Wire-Pi-Plus

  • 1-Wire® to I2C host interface with ESD protection diode.
  • Stackable with other Raspberry Pi accessory boards.
  • Buffered 5V I2C port.
  • External 5V power input for 1-Wire® interface.

The 1 Wire Pi from AB Electronics UK is a communication board supporting the 1-Wire® protocol.  A 5V buffered I2C port is also provided on the board.

The 1-Wire® port is based around a DS2482-100 I2C to 1-Wire® bridge device.  The DS2482-100 provides bi-directional protocol conversion between the I2C port on the Raspberry Pi and any attached 1-Wire® slave devices.  An ESD Protection Diode is used to protect the 1 Wire Pi and Raspberry Pi from electrostatic spikes on the 1-Wire® port.  Connections to the 1-Wire® port can be made through the RJ-12 socket or the solder points on the PCB.  See our KB page for configuring and using the 1-Wire® port on your Raspberry Pi.

A 5V input port is also provided allowing you to use an external power supply on the 1-Wire® interface, reducing the load on the Raspberry Pi.  If you choose to use the external 5V input please remove the jumper on the board to isolate the Raspberry Pi 5V bus.

A detailed tutorial has been written by Jack Creasey, author of Raspberry Pi Essentials,for the setup of OWFS with the 1 Wire Pi and 1 Wire Plus boards. View the tutorial.

Datasheets

1-Wire Pi Datasheet

DS2482S (1-Wire Interface)

Input Ratings & Specifications

Vdd (5V input pin): 5.0V

Maximum current on 1-Wire pins: ±20 mA

I2C SDA/SCL voltage: 5.0 V

I2C port current: 100 mA

Schematic

Click to download
Click to download schematic PDF.

Mechanical Drawings

Mechanical Drawing

Click image to enlarge

Sample Code

The Quick2wire lib from https://github.com/quick2wire/quick2wire-python-api allows easy access to the I2C port via Python.

Configuring and using the 1-Wire® port on your Raspberry Pi

 

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